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Add io_mesh_3mf addon #104950

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anson-liu wants to merge 1 commits from anson-liu/blender-addons:main into main
pull from: anson-liu/blender-addons:main
merge into: blender:main

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io_mesh_3mf/__init__.py Normal file
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# Blender add-on to import and export 3MF files.
# Copyright (C) 2020 Ghostkeeper
# This add-on is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
# Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
# later version.
# This add-on is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for
# details.
# You should have received a copy of the GNU Affero General Public License along with this plug-in. If not, see
# <https://gnu.org/licenses/>.
# <pep8 compliant>
bl_info = {
"name": "3MF format",
"author": "Ghostkeeper",
"version": (1, 0, 0),
"blender": (2, 80, 0),
"location": "File > Import-Export",
"description": "Import-Export 3MF files",
"category": "Import-Export"
}
"""
Import and export 3MF files in Blender.
"""
# Reload functionality.
if "bpy" in locals():
import importlib
if "import_3mf" in locals():
importlib.reload(import_3mf)
if "export_3mf" in locals():
importlib.reload(export_3mf)
import bpy.utils # To (un)register the add-on.
import bpy.types # To (un)register the add-on as an import/export function.
from .import_3mf import Import3MF # Imports 3MF files.
from .export_3mf import Export3MF # Exports 3MF files.
def menu_import(self, _):
"""
Calls the 3MF import operator from the menu item.
"""
self.layout.operator(Import3MF.bl_idname, text="3D Manufacturing Format (.3mf)")
def menu_export(self, _):
"""
Calls the 3MF export operator from the menu item.
"""
self.layout.operator(Export3MF.bl_idname, text="3D Manufacturing Format (.3mf)")
classes = (
Import3MF,
Export3MF
)
def register():
for cls in classes:
bpy.utils.register_class(cls)
bpy.types.TOPBAR_MT_file_import.append(menu_import)
bpy.types.TOPBAR_MT_file_export.append(menu_export)
def unregister():
for cls in classes:
bpy.utils.unregister_class(cls)
bpy.types.TOPBAR_MT_file_import.remove(menu_import)
bpy.types.TOPBAR_MT_file_export.remove(menu_export)
# Allow the add-on to be ran directly without installation.
if __name__ == "__main__":
register()

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io_mesh_3mf/annotations.py Normal file
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# Blender add-on to import and export 3MF files.
# Copyright (C) 2020 Ghostkeeper
# This add-on is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
# Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
# later version.
# This add-on is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for
# details.
# You should have received a copy of the GNU Affero General Public License along with this plug-in. If not, see
# <https://gnu.org/licenses/>.
# <pep8 compliant>
import bpy # To store the annotations long-term in the Blender context.
import collections # Namedtuple data structure for annotations, and Counter to write optimized content types.
import json # To serialize the data for long-term storage in the Blender scene.
import logging # Reporting parsing errors.
import os.path # To parse target paths in relationships.
import urllib.parse # To parse relative target paths in relationships.
import xml.etree.ElementTree # To parse the relationships files.
from .constants import *
# These are the different types of annotations we can store.
Relationship = collections.namedtuple("Relationship", ["namespace", "source"])
ContentType = collections.namedtuple("ContentType", ["mime_type"])
# Flag object to denote that different 3MF archives give different content types to the same file in the archive.
ConflictingContentType = object()
ANNOTATION_FILE = ".3mf_annotations" # File name to use to store the annotations in the Blender data.
class Annotations:
"""
This is a collection of annotations for a 3MF document. It annotates the files in the archive with metadata
information.
The class contains serialisation and deserialization functions in order to be able to load and save the annotations
from/to a 3MF archive, and to load and save the annotations in the Blender scene.
The annotations are stored in the `self.annotations` dictionary. The keys of this dictionary are the targets of the
annotations, normally the files in this archive. It can be any URI however, and the files don't necessarily need to
exist.
The values are sets of annotations. The annotations are named tuples as described in the beginning of this module.
The set can contain any mixture of these named tuples. Duplicates will get filtered out by the nature of the set
data structure.
"""
def __init__(self):
"""
Creates an empty collection of annotations.
"""
# All of the annotations so far. Keys are the target files of the annotations. Values are sets of annotation
# objects.
self.annotations = {}
def add_rels(self, rels_file):
"""
Add relationships to this collection from a file stream containing a .rels file from a 3MF archive.
A relationship is treated as a file annotation, because it only contains a file that the relationship is
targeting, and a meaningless namespace. The relationship also originates from a source, indicated by the path to
the relationship file. This will also get stored, so that it can be properly restored later.
Duplicate relationships won't get stored.
:param rels_file: A file stream containing a .rels file.
"""
# Relationships are evaluated relative to the path that the _rels folder around the .rels file is on. If any.
base_path = os.path.dirname(rels_file.name) + "/"
if os.path.basename(os.path.dirname(base_path)) == RELS_FOLDER:
base_path = os.path.dirname(os.path.dirname(base_path)) + "/"
try:
root = xml.etree.ElementTree.ElementTree(file=rels_file)
except xml.etree.ElementTree.ParseError as e:
logging.warning(
f"Relationship file {rels_file.name} has malformed XML (position {e.position[0]}:{e.position[1]}).")
return # Skip this file.
for relationship_node in root.iterfind(RELS_RELATIONSHIP_FIND, RELS_NAMESPACES):
try:
target = relationship_node.attrib["Target"]
namespace = relationship_node.attrib["Type"]
except KeyError as e:
logging.warning(f"Relationship missing attribute: {str(e)}")
continue # Skip this relationship.
if namespace == MODEL_REL: # Don't store relationships that we will write ourselves.
continue
# Evaluate any relative URIs based on the path to this .rels file in the archive.
target = urllib.parse.urljoin(base_path, target)
if target != "" and target[0] == "/":
# To coincide with the convention held by the zipfile package, paths in this archive will not start with
# a slash.
target = target[1:]
if target not in self.annotations:
self.annotations[target] = set()
# Add to the annotations as a relationship (since it's a set, don't create duplicates).
self.annotations[target].add(Relationship(namespace=namespace, source=base_path))
def add_content_types(self, files_by_content_type):
"""
Add annotations that signal the content types of the files in the archive.
If a file already got a different content type from a different 3MF archive, the content type of the file now
becomes unknown (and subsequently won't get stored in any exported 3MF archive).
Content types for files known to this 3MF implementation will not get stored. This add-on will rewrite those
files and may change the file location and such.
:param files_by_content_type: The files in this archive, sorted by content type.
"""
for content_type, file_set in files_by_content_type.items():
if content_type == "":
continue # Don't store content type if the content type is unknown.
if content_type in {RELS_MIMETYPE, MODEL_MIMETYPE}:
continue # Don't store content type if it's a file we'll rewrite with this add-on.
for file in file_set:
filename = file.name
if filename not in self.annotations:
self.annotations[filename] = set()
if ConflictingContentType in self.annotations[filename]:
# Content type was already conflicting through multiple previous files. It'll stay in conflict.
continue
content_type_annotations = list(filter(lambda annotation: type(annotation) == ContentType,
self.annotations[filename]))
if any(content_type_annotations) and content_type_annotations[0].mime_type != content_type:
# There was already a content type and it is different from this one.
# This file now has conflicting content types!
logging.warning(f"Found conflicting content types for file: {filename}")
for annotation in content_type_annotations:
self.annotations[filename].remove(annotation)
self.annotations[filename].add(ConflictingContentType)
else:
# No content type yet, or the existing content type is the same.
# Adding it again wouldn't have any effect if it is the same.
self.annotations[filename].add(ContentType(content_type))
def write_rels(self, archive):
"""
Write the relationship annotations in this collections to an archive as .rels files.
Multiple relationship files may be added to the archive, if relationships came from multiple sources in the
original archives.
:param archive: A zip archive to add the relationships to.
"""
current_id = 0 # Have an incrementing ID number to make all relationship IDs unique across the whole archive.
# First sort all relationships by their source, so that we know which relationship goes into which file.
# We always want to create a .rels file for the archive root, with our default relationships.
rels_by_source = {"/": set()}
for target, annotations in self.annotations.items():
for annotation in annotations:
if type(annotation) is not Relationship:
continue
if annotation.source not in rels_by_source:
rels_by_source[annotation.source] = set()
rels_by_source[annotation.source].add((target, annotation.namespace))
for source, annotations in rels_by_source.items():
if source == "/": # Writing to the archive root. Don't want to start zipfile paths with a slash.
source = ""
# Create an XML document containing all relationships for this source.
root = xml.etree.ElementTree.Element(f"{{{RELS_NAMESPACE}}}Relationships")
for target, namespace in annotations:
xml.etree.ElementTree.SubElement(root, f"{{{RELS_NAMESPACE}}}Relationship", attrib={
f"{{{RELS_NAMESPACE}}}Id": "rel" + str(current_id),
f"{{{RELS_NAMESPACE}}}Target": "/" + target,
f"{{{RELS_NAMESPACE}}}Type": namespace
})
current_id += 1
# Write relationships for files that we create.
if source == "":
xml.etree.ElementTree.SubElement(root, f"{{{RELS_NAMESPACE}}}Relationship", attrib={
f"{{{RELS_NAMESPACE}}}Id": "rel" + str(current_id),
f"{{{RELS_NAMESPACE}}}Target": "/" + MODEL_LOCATION,
f"{{{RELS_NAMESPACE}}}Type": MODEL_REL
})
current_id += 1
document = xml.etree.ElementTree.ElementTree(root)
# Write that XML document to a file.
rels_file = source + RELS_FOLDER + "/.rels" # _rels folder in the "source" folder.
with archive.open(rels_file, 'w') as f:
document.write(f, xml_declaration=True, encoding='UTF-8', default_namespace=RELS_NAMESPACE)
def write_content_types(self, archive):
"""
Write a [Content_Types].xml file to a 3MF archive, containing all of the content types that we have assigned.
:param archive: A zip archive to add the content types to.
"""
# First sort all of the content types by their extension, so that we can find out what the most common content
# type is for each extension.
content_types_by_extension = {}
for target, annotations in self.annotations.items():
for annotation in annotations:
if type(annotation) is not ContentType:
continue
extension = os.path.splitext(target)[1]
if extension not in content_types_by_extension:
content_types_by_extension[extension] = []
content_types_by_extension[extension].append(annotation.mime_type)
# Then find out which is the most common content type to assign to that extension.
most_common = {}
for extension, mime_types in content_types_by_extension.items():
counter = collections.Counter(mime_types)
most_common[extension] = counter.most_common(1)[0][0]
# Add the content types for files that this add-on creates by itself.
most_common[".rels"] = RELS_MIMETYPE
most_common[".model"] = MODEL_MIMETYPE
# Write an XML file that contains the extension rules for the most common cases,
# but specific overrides for the outliers.
root = xml.etree.ElementTree.Element(f"{{{CONTENT_TYPES_NAMESPACE}}}Types")
# First add all of the extension-based rules.
for extension, mime_type in most_common.items():
if not extension: # Skip files without extension.
continue
xml.etree.ElementTree.SubElement(root, f"{{{CONTENT_TYPES_NAMESPACE}}}Default", attrib={
f"{{{CONTENT_TYPES_NAMESPACE}}}Extension": extension[1:], # Don't include the period.
f"{{{CONTENT_TYPES_NAMESPACE}}}ContentType": mime_type
})
# Then write the overrides for files that don't have the same content type as most of their exceptions.
for target, annotations in self.annotations.items():
for annotation in annotations:
if type(annotation) is not ContentType:
continue
extension = os.path.splitext(target)[1]
if not extension or annotation.mime_type != most_common[extension]:
# This is an exceptional case that should be stored as an override.
xml.etree.ElementTree.SubElement(root, f"{{{CONTENT_TYPES_NAMESPACE}}}Override", attrib={
f"{{{CONTENT_TYPES_NAMESPACE}}}PartName": "/" + target,
f"{{{CONTENT_TYPES_NAMESPACE}}}ContentType": annotation.mime_type
})
# Output all that to the [Content_Types].xml file.
document = xml.etree.ElementTree.ElementTree(root)
with archive.open(CONTENT_TYPES_LOCATION, 'w') as f:
document.write(f, xml_declaration=True, encoding='UTF-8', default_namespace=CONTENT_TYPES_NAMESPACE)
def store(self):
"""
Stores this `Annotations` instance in the Blender scene.
The instance will serialize itself and put that data in a hidden JSON file in the scene. This way the data can
survive until it needs to be saved to a 3MF document again, even when shared through a Blend file.
"""
# Generate a JSON document containing all annotations.
document = {}
for target, annotations in self.annotations.items():
serialized_annotations = []
for annotation in annotations:
if type(annotation) == Relationship:
serialized_annotations.append({
"annotation": 'relationship',
"namespace": annotation.namespace,
"source": annotation.source
})
elif type(annotation) == ContentType:
serialized_annotations.append({
"annotation": 'content_type',
"mime_type": annotation.mime_type
})
elif annotation == ConflictingContentType:
serialized_annotations.append({
"annotation": 'content_type_conflict'
})
document[target] = serialized_annotations
# Store this in the Blender context.
if ANNOTATION_FILE in bpy.data.texts:
bpy.data.texts.remove(bpy.data.texts[ANNOTATION_FILE])
text_file = bpy.data.texts.new(ANNOTATION_FILE)
text_file.write(json.dumps(document))
def retrieve(self):
"""
Retrieves any existing annotations from the Blender scene.
This looks for a serialized annotation file in the Blender data. If it exists, it parses that file and retrieves
the data from it, restoring the state of the annotations collection that stored that file.
"""
# If there's nothing stored in the current scene, this clears the state of the annotations.
self.annotations.clear()
if ANNOTATION_FILE not in bpy.data.texts:
return # Nothing to read. Done!
try:
annotation_data = json.loads(bpy.data.texts[ANNOTATION_FILE].as_string())
except json.JSONDecodeError:
logging.warning("Annotation file exists, but is not properly formatted.")
return # File was meddled with?
for target, annotations in annotation_data.items():
self.annotations[target] = set()
try:
for annotation in annotations:
if annotation['annotation'] == 'relationship':
self.annotations[target].add(
Relationship(namespace=annotation['namespace'], source=annotation['source']))
elif annotation['annotation'] == 'content_type':
self.annotations[target].add(ContentType(mime_type=annotation['mime_type']))
elif annotation['annotation'] == 'content_type_conflict':
self.annotations[target].add(ConflictingContentType)
else:
logging.warning(f"Unknown annotation type \"{annotation['annotation']}\" encountered.")
continue
except TypeError: # Raised when `annotations` is not iterable.
logging.warning(f"Annotation for target \"{target}\" is not properly structured.")
except KeyError as e:
# Raised when missing the 'annotation' key or a required key belonging to that annotation.
logging.warning(f"Annotation for target \"{target}\" missing key: {str(e)}")
if not self.annotations[target]: # Nothing was added in the end.
del self.annotations[target] # Don't store the empty target either then.

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io_mesh_3mf/constants.py Normal file
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# Blender add-on to import and export 3MF files.
# Copyright (C) 2020 Ghostkeeper
# This add-on is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
# Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
# later version.
# This add-on is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for
# details.
# You should have received a copy of the GNU Affero General Public License along with this plug-in. If not, see
# <https://gnu.org/licenses/>.
# <pep8 compliant>
"""
This module defines some constants for 3MF's file structure.
These are the constants that are inherent to the 3MF file format.
"""
SUPPORTED_EXTENSIONS = set() # Set of namespaces for 3MF extensions that we support.
# File contents to use when files must be preserved but there's a file with different content in a previous archive.
# Only for flagging. This will not be in the final 3MF archives.
conflicting_mustpreserve_contents = "<Conflicting MustPreserve file!>"
# Default storage locations.
MODEL_LOCATION = "3D/3dmodel.model" # Conventional location for the 3D model data.
CONTENT_TYPES_LOCATION = "[Content_Types].xml" # Location of the content types definition.
RELS_FOLDER = "_rels" # Folder name to store relationships files in.
# Relationship types.
MODEL_REL = "http://schemas.microsoft.com/3dmanufacturing/2013/01/3dmodel" # Relationship type of 3D models.
THUMBNAIL_REL = "http://schemas.openxmlformats.org/package/2006/relationships/metadata/thumbnail"
# MIME types of files in the archive.
RELS_MIMETYPE = "application/vnd.openxmlformats-package.relationships+xml" # MIME type of .rels files.
MODEL_MIMETYPE = "application/vnd.ms-package.3dmanufacturing-3dmodel+xml" # MIME type of .model files.
# Constants in the 3D model file.
MODEL_NAMESPACE = "http://schemas.microsoft.com/3dmanufacturing/core/2015/02"
MODEL_NAMESPACES = {
"3mf": MODEL_NAMESPACE
}
MODEL_DEFAULT_UNIT = "millimeter" # If the unit is missing, it will be this.
# Constants in the ContentTypes file.
CONTENT_TYPES_NAMESPACE = "http://schemas.openxmlformats.org/package/2006/content-types"
CONTENT_TYPES_NAMESPACES = {
"ct": CONTENT_TYPES_NAMESPACE
}
# Constants in the .rels files.
RELS_NAMESPACE = "http://schemas.openxmlformats.org/package/2006/relationships"
RELS_NAMESPACES = { # Namespaces used for the rels files.
"rel": RELS_NAMESPACE
}
RELS_RELATIONSHIP_FIND = "rel:Relationship"

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io_mesh_3mf/export_3mf.py Normal file
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# Blender add-on to import and export 3MF files.
# Copyright (C) 2020 Ghostkeeper
# This add-on is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
# Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
# later version.
# This add-on is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for
# details.
# You should have received a copy of the GNU Affero General Public License along with this plug-in. If not, see
# <https://gnu.org/licenses/>.
# <pep8 compliant>
import base64 # To decode files that must be preserved.
import bpy # The Blender API.
import bpy.props # To define metadata properties for the operator.
import bpy.types # This class is an operator in Blender, and to find meshes in the scene.
import bpy_extras.io_utils # Helper functions to export meshes more easily.
import bpy_extras.node_shader_utils # Converting material colors to sRGB.
import collections # Counter, to find the most common material of an object.
import itertools
import logging # To debug and log progress.
import mathutils # For the transformation matrices.
import xml.etree.ElementTree # To write XML documents with the 3D model data.
import zipfile # To write zip archives, the shell of the 3MF file.
from .annotations import Annotations # To store file annotations
from .constants import *
from .metadata import Metadata # To store metadata from the Blender scene into the 3MF file.
from .unit_conversions import blender_to_metre, threemf_to_metre
log = logging.getLogger(__name__)
class Export3MF(bpy.types.Operator, bpy_extras.io_utils.ExportHelper):
"""
Operator that exports a 3MF file from Blender.
"""
# Metadata.
bl_idname = "export_mesh.threemf"
bl_label = "Export 3MF"
bl_description = "Save the current scene to 3MF"
filename_ext = ".3mf"
# Options for the user.
filter_glob: bpy.props.StringProperty(
default="*.3mf",
options={'HIDDEN'})
use_selection: bpy.props.BoolProperty(
name="Selection Only",
description="Export selected objects only.",
default=False)
global_scale: bpy.props.FloatProperty(
name="Scale",
default=1.0,
soft_min=0.001,
soft_max=1000.0,
min=1e-6,
max=1e6)
use_mesh_modifiers: bpy.props.BoolProperty(
name="Apply Modifiers",
description="Apply the modifiers before saving.",
default=True)
coordinate_precision: bpy.props.IntProperty(
name="Precision",
description="The number of decimal digits to use in coordinates in the file.",
default=4,
min=0,
max=12)
def __init__(self):
"""
Initialize some fields with defaults before starting.
"""
super().__init__()
self.next_resource_id = 1 # Which resource ID to generate for the next object.
self.num_written = 0 # How many objects we've written to the file.
self.material_resource_id = -1 # We write one material. This is the resource ID of that material.
self.material_name_to_index = {} # For each material in Blender, the index in the 3MF materials group.
def execute(self, context):
"""
The main routine that writes the 3MF archive.
This function serves as a high-level overview of the steps involved to write a 3MF file.
:param context: The Blender context.
:return: A set of status flags to indicate whether the write succeeded or not.
"""
# Reset state.
self.next_resource_id = 1 # Starts counting at 1 for some inscrutable reason.
self.material_resource_id = -1
self.num_written = 0
archive = self.create_archive(self.filepath)
if archive is None:
return {'CANCELLED'}
if self.use_selection:
blender_objects = context.selected_objects
else:
blender_objects = context.scene.objects
global_scale = self.unit_scale(context)
# Due to an open bug in Python 3.7 (Blender's version) we need to prefix all elements with the namespace.
# Bug: https://bugs.python.org/issue17088
# Workaround: https://stackoverflow.com/questions/4997848/4999510#4999510
root = xml.etree.ElementTree.Element(f"{{{MODEL_NAMESPACE}}}model")
scene_metadata = Metadata()
scene_metadata.retrieve(bpy.context.scene)
self.write_metadata(root, scene_metadata)
resources_element = xml.etree.ElementTree.SubElement(root, f"{{{MODEL_NAMESPACE}}}resources")
self.material_name_to_index = self.write_materials(resources_element, blender_objects)
self.write_objects(root, resources_element, blender_objects, global_scale)
document = xml.etree.ElementTree.ElementTree(root)
with archive.open(MODEL_LOCATION, 'w', force_zip64=True) as f:
document.write(f, xml_declaration=True, encoding='UTF-8', default_namespace=MODEL_NAMESPACE)
try:
archive.close()
except EnvironmentError as e:
log.error(f"Unable to complete writing to 3MF archive: {e}")
return {'CANCELLED'}
log.info(f"Exported {self.num_written} objects to 3MF archive {self.filepath}.")
return {'FINISHED'}
# The rest of the functions are in order of when they are called.
def create_archive(self, filepath):
"""
Creates an empty 3MF archive.
The archive is complete according to the 3MF specs except that the actual 3dmodel.model file is missing.
:param filepath: The path to write the file to.
:return: A zip archive that other functions can add things to.
"""
try:
archive = zipfile.ZipFile(filepath, 'w', compression=zipfile.ZIP_DEFLATED, compresslevel=9)
# Store the file annotations we got from imported 3MF files, and store them in the archive.
annotations = Annotations()
annotations.retrieve()
annotations.write_rels(archive)
annotations.write_content_types(archive)
self.must_preserve(archive)
except EnvironmentError as e:
log.error(f"Unable to write 3MF archive to {filepath}: {e}")
return None
return archive
def must_preserve(self, archive):
"""
Write files that must be preserved to the archive.
These files were stored in the Blender scene in a hidden location.
:param archive: The archive to write files to.
"""
for textfile in bpy.data.texts:
filename = textfile.name
if not filename.startswith(".3mf_preserved/"):
continue # Unrelated file. Not ours to read.
contents = textfile.as_string()
if contents == conflicting_mustpreserve_contents:
continue # This file was in conflict. Don't preserve any copy of it then.
contents = base64.b85decode(contents.encode("UTF-8"))
filename = filename[len(".3mf_preserved/"):]
with archive.open(filename, 'w') as f:
f.write(contents)
def unit_scale(self, context):
"""
Get the scaling factor we need to transform the document to millimetres.
:param context: The Blender context to get the unit from.
:return: Floating point value that we need to scale this model by. A small number (<1) means that we need to
make the coordinates in the 3MF file smaller than the coordinates in Blender. A large number (>1) means we need
to make the coordinates in the file larger than the coordinates in Blender.
"""
scale = self.global_scale
if context.scene.unit_settings.scale_length != 0:
scale *= context.scene.unit_settings.scale_length # Apply the global scale of the units in Blender.
threemf_unit = MODEL_DEFAULT_UNIT
blender_unit = context.scene.unit_settings.length_unit
scale /= threemf_to_metre[threemf_unit] # Convert 3MF units to metre.
scale *= blender_to_metre[blender_unit] # Convert metre to Blender's units.
return scale
def write_materials(self, resources_element, blender_objects):
"""
Write the materials on the specified blender objects to a 3MF document.
We'll write all materials to one single <basematerials> tag in the resources.
Aside from writing the materials to the document, this function also returns a mapping from the names of the
materials in Blender (which must be unique) to the index in the <basematerials> material group. Using that
mapping, the objects and triangles can write down an index referring to the list of <base> tags.
Since the <base> material can only hold a color, we'll write the diffuse color of the material to the file.
:param resources_element: A <resources> node from a 3MF document.
:param blender_objects: A list of Blender objects that may have materials which we need to write to the
document.
:return: A mapping from material name to the index of that material in the <basematerials> tag.
"""
name_to_index = {} # The output list, mapping from material name to indexes in the <basematerials> tag.
next_index = 0
# Create an element lazily. We don't want to create an element if there are no materials to write.
basematerials_element = None
for blender_object in blender_objects:
for material_slot in blender_object.material_slots:
material = material_slot.material
material_name = material.name
if material_name in name_to_index: # Already have this material through another object.
continue
# Wrap this material into a principled render node, to convert its color to sRGB.
principled = bpy_extras.node_shader_utils.PrincipledBSDFWrapper(material, is_readonly=True)
color = principled.base_color
red = min(255, round(color[0] * 255))
green = min(255, round(color[1] * 255))
blue = min(255, round(color[2] * 255))
alpha = principled.alpha
if alpha >= 1.0: # Completely opaque. Leave out the alpha component.
color_hex = "#%0.2X%0.2X%0.2X" % (red, green, blue)
else:
alpha = min(255, round(alpha * 255))
color_hex = "#%0.2X%0.2X%0.2X%0.2X" % (red, green, blue, alpha)
if basematerials_element is None:
self.material_resource_id = str(self.next_resource_id)
self.next_resource_id += 1
basematerials_element = xml.etree.ElementTree.SubElement(
resources_element,
f"{{{MODEL_NAMESPACE}}}basematerials", attrib={
f"{{{MODEL_NAMESPACE}}}id": self.material_resource_id
})
xml.etree.ElementTree.SubElement(basematerials_element, f"{{{MODEL_NAMESPACE}}}base", attrib={
f"{{{MODEL_NAMESPACE}}}name": material_name,
f"{{{MODEL_NAMESPACE}}}displaycolor": color_hex
})
name_to_index[material_name] = next_index
next_index += 1
return name_to_index
def write_objects(self, root, resources_element, blender_objects, global_scale):
"""
Writes a group of objects into the 3MF archive.
:param root: An XML root element to write the objects into.
:param resources_element: An XML element to write resources into.
:param blender_objects: A list of Blender objects that need to be written to that XML element.
:param global_scale: A scaling factor to apply to all objects to convert the units.
"""
transformation = mathutils.Matrix.Scale(global_scale, 4)
build_element = xml.etree.ElementTree.SubElement(root, f"{{{MODEL_NAMESPACE}}}build")
for blender_object in blender_objects:
if blender_object.parent is not None:
continue # Only write objects that have no parent, since we'll get the child objects recursively.
if blender_object.type not in {'MESH', 'EMPTY'}:
continue
objectid, mesh_transformation = self.write_object_resource(resources_element, blender_object)
item_element = xml.etree.ElementTree.SubElement(build_element, f"{{{MODEL_NAMESPACE}}}item")
self.num_written += 1
item_element.attrib[f"{{{MODEL_NAMESPACE}}}objectid"] = str(objectid)
mesh_transformation = transformation @ mesh_transformation
if mesh_transformation != mathutils.Matrix.Identity(4):
item_element.attrib[f"{{{MODEL_NAMESPACE}}}transform"] =\
self.format_transformation(mesh_transformation)
metadata = Metadata()
metadata.retrieve(blender_object)
if "3mf:partnumber" in metadata:
item_element.attrib[f"{{{MODEL_NAMESPACE}}}partnumber"] = metadata["3mf:partnumber"].value
del metadata["3mf:partnumber"]
if metadata:
metadatagroup_element = xml.etree.ElementTree.SubElement(
item_element,
f"{{{MODEL_NAMESPACE}}}metadatagroup")
self.write_metadata(metadatagroup_element, metadata)
def write_object_resource(self, resources_element, blender_object):
"""
Write a single Blender object and all of its children to the resources of a 3MF document.
If the object contains a mesh it'll get written to the document as an object with a mesh resource. If the object
contains children it'll get written to the document as an object with components. If the object contains both,
two objects will be written; one with the mesh and another with the components. The mesh then gets added as a
component of the object with components.
:param resources_element: The <resources> element of the 3MF document to write into.
:param blender_object: A Blender object to write to that XML element.
:return: A tuple, containing the object ID of the newly written resource and a transformation matrix that this
resource must be saved with.
"""
new_resource_id = self.next_resource_id
self.next_resource_id += 1
object_element = xml.etree.ElementTree.SubElement(resources_element, f"{{{MODEL_NAMESPACE}}}object")
object_element.attrib[f"{{{MODEL_NAMESPACE}}}id"] = str(new_resource_id)
metadata = Metadata()
metadata.retrieve(blender_object)
if "3mf:object_type" in metadata:
object_type = metadata["3mf:object_type"].value
if object_type != "model": # Only write if not the default.
object_element.attrib[f"{{{MODEL_NAMESPACE}}}type"] = object_type
del metadata["3mf:object_type"]
if blender_object.mode == 'EDIT':
blender_object.update_from_editmode() # Apply recent changes made to the model.
mesh_transformation = blender_object.matrix_world
child_objects = blender_object.children
if child_objects: # Only write the <components> tag if there are actually components.
components_element = xml.etree.ElementTree.SubElement(
object_element,
f"{{{MODEL_NAMESPACE}}}components")
for child in blender_object.children:
if child.type != 'MESH':
continue
# Recursively write children to the resources.
child_id, child_transformation = self.write_object_resource(resources_element, child)
# Use pseudo-inverse for safety, but the epsilon then doesn't matter since it'll get multiplied by 0
# later anyway then.
child_transformation = mesh_transformation.inverted_safe() @ child_transformation
component_element = xml.etree.ElementTree.SubElement(
components_element,
f"{{{MODEL_NAMESPACE}}}component")
self.num_written += 1
component_element.attrib[f"{{{MODEL_NAMESPACE}}}objectid"] = str(child_id)
if child_transformation != mathutils.Matrix.Identity(4):
component_element.attrib[f"{{{MODEL_NAMESPACE}}}transform"] =\
self.format_transformation(child_transformation)
# In the tail recursion, get the vertex data.
# This is necessary because we may need to apply the mesh modifiers, which causes these objects to lose their
# children.
if self.use_mesh_modifiers:
dependency_graph = bpy.context.evaluated_depsgraph_get()
blender_object = blender_object.evaluated_get(dependency_graph)
try:
mesh = blender_object.to_mesh()
except RuntimeError: # Object.to_mesh() is not guaranteed to return Optional[Mesh], apparently.
return new_resource_id, mesh_transformation
if mesh is None:
return new_resource_id, mesh_transformation
# Need to convert this to triangles-only, because 3MF doesn't support faces with more than 3 vertices.
mesh.calc_loop_triangles()
if len(mesh.vertices) > 0: # Only write a <mesh> tag if there is mesh data.
# If this object already contains components, we can't also store a mesh. So create a new object and use
# that object as another component.
if child_objects:
mesh_id = self.next_resource_id
self.next_resource_id += 1
mesh_object_element = xml.etree.ElementTree.SubElement(
resources_element,
f"{{{MODEL_NAMESPACE}}}object")
mesh_object_element.attrib[f"{{{MODEL_NAMESPACE}}}id"] = str(mesh_id)
component_element = xml.etree.ElementTree.SubElement(
components_element,
f"{{{MODEL_NAMESPACE}}}component")
self.num_written += 1
component_element.attrib[f"{{{MODEL_NAMESPACE}}}objectid"] = str(mesh_id)
else: # No components, then we can write directly into this object resource.
mesh_object_element = object_element
mesh_element = xml.etree.ElementTree.SubElement(mesh_object_element, f"{{{MODEL_NAMESPACE}}}mesh")
# Find the most common material for this mesh, for maximum compression.
material_indices = [triangle.material_index for triangle in mesh.loop_triangles]
# If there are no triangles, we provide 0 as index, but it'll not get read by write_triangles either then.
most_common_material_list_index = 0
if material_indices and blender_object.material_slots:
counter = collections.Counter(material_indices)
# most_common_material_object_index is an index from the MeshLoopTriangle, referring to the list of
# materials attached to the Blender object.
most_common_material_object_index = counter.most_common(1)[0][0]
most_common_material = blender_object.material_slots[most_common_material_object_index].material
# most_common_material_list_index is an index referring to our own list of materials that we put in the
# resources.
most_common_material_list_index = self.material_name_to_index[most_common_material.name]
# We always only write one group of materials. The resource ID was determined when it was written.
object_element.attrib[f"{{{MODEL_NAMESPACE}}}pid"] = str(self.material_resource_id)
object_element.attrib[f"{{{MODEL_NAMESPACE}}}pindex"] = str(most_common_material_list_index)
self.write_vertices(mesh_element, mesh.vertices)
self.write_triangles(
mesh_element,
mesh.loop_triangles,
most_common_material_list_index,
blender_object.material_slots)
# If the object has metadata, write that to a metadata object.
if "3mf:partnumber" in metadata:
mesh_object_element.attrib[f"{{{MODEL_NAMESPACE}}}partnumber"] =\
metadata["3mf:partnumber"].value
del metadata["3mf:partnumber"]
if "3mf:object_type" in metadata:
object_type = metadata["3mf:object_type"].value
if object_type != "model" and object_type != "other":
# Only write if not the default.
# Don't write "other" object types since we're not allowed to refer to them. Pretend they are normal
# models.
mesh_object_element.attrib[f"{{{MODEL_NAMESPACE}}}type"] = object_type
del metadata["3mf:object_type"]
if metadata:
metadatagroup_element = xml.etree.ElementTree.SubElement(
object_element,
f"{{{MODEL_NAMESPACE}}}metadatagroup")
self.write_metadata(metadatagroup_element, metadata)
return new_resource_id, mesh_transformation
def write_metadata(self, node, metadata):
"""
Writes metadata from a metadata storage into an XML node.
:param node: The node to add <metadata> tags to.
:param metadata: The collection of metadata to write to that node.
"""
for metadata_entry in metadata.values():
metadata_node = xml.etree.ElementTree.SubElement(node, f"{{{MODEL_NAMESPACE}}}metadata")
metadata_node.attrib[f"{{{MODEL_NAMESPACE}}}name"] = metadata_entry.name
if metadata_entry.preserve:
metadata_node.attrib[f"{{{MODEL_NAMESPACE}}}preserve"] = "1"
if metadata_entry.datatype:
metadata_node.attrib[f"{{{MODEL_NAMESPACE}}}type"] = metadata_entry.datatype
metadata_node.text = metadata_entry.value
def format_transformation(self, transformation):
"""
Formats a transformation matrix in 3MF's formatting.
This transformation matrix can then be written to an attribute.
:param transformation: The transformation matrix to format.
:return: A serialisation of the transformation matrix.
"""
pieces = (row[:3] for row in transformation.transposed()) # Don't convert the 4th column.
result = ""
for cell in itertools.chain.from_iterable(pieces):
if result != "": # First loop, don't put a space in.
result += " "
result += self.format_number(cell, 6) # Never use scientific notation!
return result
def write_vertices(self, mesh_element, vertices):
"""
Writes a list of vertices into the specified mesh element.
This then becomes a resource that can be used in a build.
:param mesh_element: The <mesh> element of the 3MF document.
:param vertices: A list of Blender vertices to add.
"""
vertices_element = xml.etree.ElementTree.SubElement(mesh_element, f"{{{MODEL_NAMESPACE}}}vertices")
# Precompute some names for better performance.
vertex_name = f"{{{MODEL_NAMESPACE}}}vertex"
x_name = f"{{{MODEL_NAMESPACE}}}x"
y_name = f"{{{MODEL_NAMESPACE}}}y"
z_name = f"{{{MODEL_NAMESPACE}}}z"
for vertex in vertices: # Create the <vertex> elements.
vertex_element = xml.etree.ElementTree.SubElement(vertices_element, vertex_name)
vertex_element.attrib[x_name] = self.format_number(vertex.co[0], self.coordinate_precision)
vertex_element.attrib[y_name] = self.format_number(vertex.co[1], self.coordinate_precision)
vertex_element.attrib[z_name] = self.format_number(vertex.co[2], self.coordinate_precision)
def write_triangles(self, mesh_element, triangles, object_material_list_index, material_slots):
"""
Writes a list of triangles into the specified mesh element.
This then becomes a resource that can be used in a build.
:param mesh_element: The <mesh> element of the 3MF document.
:param triangles: A list of triangles. Each list is a list of indices to the list of vertices.
:param object_material_list_index: The index of the material that the object was written with to which these
triangles belong. If the triangle has a different index, we need to write the index with the triangle.
:param material_slots: List of materials belonging to the object for which we write triangles. These are
necessary to interpret the material indices stored in the MeshLoopTriangles.
"""
triangles_element = xml.etree.ElementTree.SubElement(mesh_element, f"{{{MODEL_NAMESPACE}}}triangles")
# Precompute some names for better performance.
triangle_name = f"{{{MODEL_NAMESPACE}}}triangle"
v1_name = f"{{{MODEL_NAMESPACE}}}v1"
v2_name = f"{{{MODEL_NAMESPACE}}}v2"
v3_name = f"{{{MODEL_NAMESPACE}}}v3"
p1_name = f"{{{MODEL_NAMESPACE}}}p1"
for triangle in triangles:
triangle_element = xml.etree.ElementTree.SubElement(triangles_element, triangle_name)
triangle_element.attrib[v1_name] = str(triangle.vertices[0])
triangle_element.attrib[v2_name] = str(triangle.vertices[1])
triangle_element.attrib[v3_name] = str(triangle.vertices[2])
if triangle.material_index < len(material_slots):
# Convert to index in our global list.
material_index = self.material_name_to_index[material_slots[triangle.material_index].material.name]
if material_index != object_material_list_index:
# Not equal to the index that our parent object was written with, so we must override it here.
triangle_element.attrib[p1_name] = str(material_index)
def format_number(self, number, decimals):
"""
Properly formats a floating point number to a certain precision.
This format will never use scientific notation (no 3.14e-5 nonsense) and will have a fixed limit to the number
of decimals. It will not have a limit to the length of the integer part. Any trailing zeros are stripped.
:param number: A floating point number to format.
:param decimals: The maximum number of places after the radix to write.
:return: A string representing that number.
"""
formatted = ("{:." + str(decimals) + "f}").format(number).rstrip("0").rstrip(".")
if formatted == "":
return "0"
return formatted

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# Blender add-on to import and export 3MF files.
# Copyright (C) 2020 Ghostkeeper
# This add-on is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
# Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option)
# any later version.
# This add-on is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for
# details.
# You should have received a copy of the GNU Affero General Public License along with this plug-in. If not, see
# <https://gnu.org/licenses/>.
# <pep8 compliant>
import base64 # To encode MustPreserve files in the Blender scene.
import bpy # The Blender API.
import bpy.ops # To adjust the camera to fit models.
import bpy.props # To define metadata properties for the operator.
import bpy.types # This class is an operator in Blender.
import bpy_extras.io_utils # Helper functions to import meshes more easily.
import bpy_extras.node_shader_utils # Getting correct color spaces for materials.
import logging # To debug and log progress.
import collections # For namedtuple.
import mathutils # For the transformation matrices.
import os.path # To take file paths relative to the selected directory.
import re # To find files in the archive based on the content types.
import xml.etree.ElementTree # To parse the 3dmodel.model file.
import zipfile # To read the 3MF files which are secretly zip archives.
from .annotations import Annotations, ContentType, Relationship # To use annotations to decide on what to import.
from .constants import *
from .metadata import MetadataEntry, Metadata # To store and serialize metadata.
from .unit_conversions import blender_to_metre, threemf_to_metre # To convert to Blender's units.
log = logging.getLogger(__name__)
ResourceObject = collections.namedtuple("ResourceObject", [
"vertices",
"triangles",
"materials",
"components",
"metadata"])
Component = collections.namedtuple("Component", ["resource_object", "transformation"])
ResourceMaterial = collections.namedtuple("ResourceMaterial", ["name", "color"])
class Import3MF(bpy.types.Operator, bpy_extras.io_utils.ImportHelper):
"""
Operator that imports a 3MF file into Blender.
"""
# Metadata.
bl_idname = "import_mesh.threemf"
bl_label = "Import 3MF"
bl_description = "Load a 3MF scene"
bl_options = {'UNDO'}
filename_ext = ".3mf"
# Options for the user.
filter_glob: bpy.props.StringProperty(default="*.3mf", options={'HIDDEN'})
files: bpy.props.CollectionProperty(name="File Path", type=bpy.types.OperatorFileListElement)
directory: bpy.props.StringProperty(subtype='DIR_PATH')
global_scale: bpy.props.FloatProperty(name="Scale", default=1.0, soft_min=0.001, soft_max=1000.0, min=1e-6, max=1e6)
def __init__(self):
"""
Initializes the importer with empty fields.
"""
super().__init__()
self.resource_objects = {} # Dictionary mapping resource IDs to ResourceObjects.
# Dictionary mapping resource IDs to dictionaries mapping indexes to ResourceMaterial objects.
self.resource_materials = {}
# Which of our resource materials already exists in the Blender scene as a Blender material.
self.resource_to_material = {}
self.num_loaded = 0
def execute(self, context):
"""
The main routine that reads out the 3MF file.
This function serves as a high-level overview of the steps involved to read the 3MF file.
:param context: The Blender context.
:return: A set of status flags to indicate whether the operation succeeded or not.
"""
# Reset state.
self.resource_objects = {}
self.resource_materials = {}
self.resource_to_material = {}
self.num_loaded = 0
scene_metadata = Metadata()
# If there was already metadata in the scene, combine that with this file.
scene_metadata.retrieve(bpy.context.scene)
# Don't load the title from the old scene. If there is a title in the imported 3MF, use that.
# Else, we'll not override the scene title and it gets retained.
del scene_metadata["Title"]
annotations = Annotations()
annotations.retrieve() # If there were already annotations in the scene, combine that with this file.
# Preparation of the input parameters.
paths = [os.path.join(self.directory, name.name) for name in self.files]
if not paths:
paths.append(self.filepath)
if bpy.ops.object.mode_set.poll():
bpy.ops.object.mode_set(mode='OBJECT') # Switch to object mode to view the new file.
if bpy.ops.object.select_all.poll():
bpy.ops.object.select_all(action='DESELECT') # Deselect other files.
for path in paths:
files_by_content_type = self.read_archive(path) # Get the files from the archive.
# File metadata.
for rels_file in files_by_content_type.get(RELS_MIMETYPE, []):
annotations.add_rels(rels_file)
annotations.add_content_types(files_by_content_type)
self.must_preserve(files_by_content_type, annotations)
# Read the model data.
for model_file in files_by_content_type.get(MODEL_MIMETYPE, []):
try:
document = xml.etree.ElementTree.ElementTree(file=model_file)
except xml.etree.ElementTree.ParseError as e:
log.error(f"3MF document in {path} is malformed: {str(e)}")
continue
if document is None:
# This file is corrupt or we can't read it. There is no error code to communicate this to Blender
# though.
continue # Leave the scene empty / skip this file.
root = document.getroot()
if not self.is_supported(root.attrib.get("requiredextensions", "")):
log.warning(f"3MF document in {path} requires unknown extensions.")
# Still continue processing even though the spec says not to. Our aim is to retrieve whatever
# information we can.
scale_unit = self.unit_scale(context, root)
self.resource_objects = {}
self.resource_materials = {}
scene_metadata = self.read_metadata(root, scene_metadata)
self.read_materials(root)
self.read_objects(root)
self.build_items(root, scale_unit)
scene_metadata.store(bpy.context.scene)
annotations.store()
# Zoom the camera to view the imported objects.
for area in bpy.context.screen.areas:
if area.type == 'VIEW_3D':
for region in area.regions:
if region.type == 'WINDOW':
override = {'area': area, 'region': region, 'edit_object': bpy.context.edit_object}
bpy.ops.view3d.view_selected(override)
log.info(f"Imported {self.num_loaded} objects from 3MF files.")
return {'FINISHED'}
# The rest of the functions are in order of when they are called.
def read_archive(self, path):
"""
Creates file streams from all the files in the archive.
The results are sorted by their content types. Consumers of this data can pick the content types that they know
from the file and process those.
:param path: The path to the archive to read.
:return: A dictionary with all of the resources in the archive by content type. The keys in this dictionary are
the different content types available in the file. The values in this dictionary are lists of input streams
referring to files in the archive.
"""
result = {}
try:
archive = zipfile.ZipFile(path)
content_types = self.read_content_types(archive)
mime_types = self.assign_content_types(archive, content_types)
for path, mime_type in mime_types.items():
if mime_type not in result:
result[mime_type] = []
# Zipfile can open an infinite number of streams at the same time. Don't worry about it.
result[mime_type].append(archive.open(path))
except (zipfile.BadZipFile, EnvironmentError) as e:
# File is corrupt, or the OS prevents us from reading it (doesn't exist, no permissions, etc.)
log.error(f"Unable to read archive: {e}")
return result
return result
def read_content_types(self, archive):
"""
Read the content types from a 3MF archive.
The output of this reading is a list of MIME types that are each mapped to a regular expression that matches on
the file paths within the archive that could contain this content type. This encodes both types of descriptors
for the content types that can occur in the content types document: Extensions and full paths.
The output is ordered in priority. Matches that should be evaluated first will be put in the front of the output
list.
:param archive: The 3MF archive to read the contents from.
:return: A list of tuples, in order of importance, where the first element describes a regex of paths that
match, and the second element is the MIME type string of the content type.
"""
namespaces = {"ct": "http://schemas.openxmlformats.org/package/2006/content-types"}
result = []
try:
with archive.open(CONTENT_TYPES_LOCATION) as f:
try:
root = xml.etree.ElementTree.ElementTree(file=f)
except xml.etree.ElementTree.ParseError as e:
log.warning(
f"{CONTENT_TYPES_LOCATION} has malformed XML"
f"(position {e.position[0]}:{e.position[1]}).")
root = None
if root is not None:
# Overrides are more important than defaults, so put those in front.
for override_node in root.iterfind("ct:Override", namespaces):
if "PartName" not in override_node.attrib or "ContentType" not in override_node.attrib:
log.warning("[Content_Types].xml malformed: Override node without path or MIME type.")
continue # Ignore the broken one.
match_regex = re.compile(re.escape(override_node.attrib["PartName"]))
result.append((match_regex, override_node.attrib["ContentType"]))
for default_node in root.iterfind("ct:Default", namespaces):
if "Extension" not in default_node.attrib or "ContentType" not in default_node.attrib:
log.warning("[Content_Types].xml malformed: Default node without extension or MIME type.")
continue # Ignore the broken one.
match_regex = re.compile(r".*\." + re.escape(default_node.attrib["Extension"]))
result.append((match_regex, default_node.attrib["ContentType"]))
except KeyError: # ZipFile reports that the content types file doesn't exist.
log.warning(f"{CONTENT_TYPES_LOCATION} file missing!")
# This parser should be robust to slightly broken files and retrieve what we can.
# In case the document is broken or missing, here we'll append the default ones for 3MF.
# If the content types file was fine, this gets least priority so the actual data still wins.
result.append((re.compile(r".*\.rels"), RELS_MIMETYPE))
result.append((re.compile(r".*\.model"), MODEL_MIMETYPE))
return result
def assign_content_types(self, archive, content_types):
"""
Assign a MIME type to each file in the archive.
The MIME types are obtained through the content types file from the archive. This content types file itself is
not in the result though.
:param archive: A 3MF archive with files to assign content types to.
:param content_types: The content types for files in that archive, in order of priority.
:return: A dictionary mapping all file paths in the archive to a content types. If the content type for a file
is unknown, the content type will be an empty string.
"""
result = {}
for file_info in archive.filelist:
file_path = file_info.filename
if file_path == CONTENT_TYPES_LOCATION: # Don't index this one.
continue
for pattern, content_type in content_types: # Process in the correct order!
if pattern.fullmatch(file_path):
result[file_path] = content_type
break
else: # None of the patterns matched.
result[file_path] = ""
return result
def must_preserve(self, files_by_content_type, annotations):
"""
Preserves files that are marked with the 'MustPreserve' relationship and PrintTickets.
These files are saved in the Blender context as text files in a hidden folder. If the preserved files are in
conflict with previously loaded 3MF archives (same file path, different content) then they will not be
preserved.
Archived files are stored in Base85 encoding to allow storing arbitrary files, even binary files. This sadly
means that the file size will increase by about 25%, and that the files are not human-readable any more when
opened in Blender, even if they were originally human-readable.
:param files_by_content_type: The files in this 3MF archive, by content type. They must be provided by content
type because that is how the ``read_archive`` function stores them, which is not ideal. But this function will
sort that out.
:param annotations: Collection of annotations gathered so far.
"""
preserved_files = set() # Find all files which must be preserved according to the annotations.
for target, its_annotations in annotations.annotations.items():
for annotation in its_annotations:
if type(annotation) == Relationship:
if annotation.namespace in {
"http://schemas.openxmlformats.org/package/2006/relationships/mustpreserve",
"http://schemas.microsoft.com/3dmanufacturing/2013/01/printticket"
}:
preserved_files.add(target)
elif type(annotation) == ContentType:
if annotation.mime_type == "application/vnd.ms-printing.printticket+xml":
preserved_files.add(target)
for files in files_by_content_type.values():
for file in files:
if file.name in preserved_files:
filename = ".3mf_preserved/" + file.name
if filename in bpy.data.texts:
if bpy.data.texts[filename].as_string() == conflicting_mustpreserve_contents:
# This file was previously already in conflict. The new file will always be in conflict with
# one of the previous files.
continue
# Encode as Base85 so that the file can be saved in Blender's Text objects.
file_contents = base64.b85encode(file.read()).decode('UTF-8')
if filename in bpy.data.texts:
if bpy.data.texts[filename].as_string() == file_contents:
# File contents are EXACTLY the same, so the file is not in conflict.
continue # But we also don't need to re-add the same file then.
else: # Same file exists with different contents, so they are in conflict.
bpy.data.texts[filename].clear()
bpy.data.texts[filename].write(conflicting_mustpreserve_contents)
continue
else: # File doesn't exist yet.
handle = bpy.data.texts.new(filename)
handle.write(file_contents)
def is_supported(self, required_extensions):
"""
Determines if a document is supported by this add-on.
:param required_extensions: The value of the `requiredextensions` attribute of the root node of the XML
document.
:return: `True` if the document is supported, or `False` if it's not.
"""
extensions = required_extensions.split(" ")
extensions = set(filter(lambda x: x != "", extensions))
return extensions <= SUPPORTED_EXTENSIONS
def unit_scale(self, context, root):
"""
Get the scaling factor we need to use for this document, according to its unit.
:param context: The Blender context.
:param root: An ElementTree root element containing the entire 3MF file.
:return: Floating point value that we need to scale this model by. A small number (<1) means that we need to
make the coordinates in Blender smaller than the coordinates in the file. A large number (>1) means we need to
make the coordinates in Blender larger than the coordinates in the file.
"""
scale = self.global_scale
if context.scene.unit_settings.scale_length != 0:
scale /= context.scene.unit_settings.scale_length # Apply the global scale of the units in Blender.
threemf_unit = root.attrib.get("unit", MODEL_DEFAULT_UNIT)
blender_unit = context.scene.unit_settings.length_unit
scale *= threemf_to_metre[threemf_unit] # Convert 3MF units to metre.
scale /= blender_to_metre[blender_unit] # Convert metre to Blender's units.
return scale
def read_metadata(self, node, original_metadata=None):
"""
Reads the metadata tags from a metadata group.
:param node: A node in the 3MF document that contains <metadata> tags. This can be either a root node, or a
<metadatagroup> node.
:param original_metadata: If there was already metadata for this context from other documents, you can provide
that metadata here. The metadata of those documents will be combined then.
:return: A `Metadata` object.
"""
if original_metadata is not None:
metadata = original_metadata
else:
metadata = Metadata() # Create a new Metadata object.
for metadata_node in node.iterfind("./3mf:metadata", MODEL_NAMESPACES):
if "name" not in metadata_node.attrib:
log.warning("Metadata entry without name is discarded.")
continue # This attribute has no name, so there's no key by which I can save the metadata.
name = metadata_node.attrib["name"]
preserve_str = metadata_node.attrib.get("preserve", "0")
# We don't use this ourselves since we always preserve, but the preserve attribute itself will also be
# preserved.
preserve = preserve_str != "0" and preserve_str.lower() != "false"
datatype = metadata_node.attrib.get("type", "")
value = metadata_node.text
# Always store all metadata so that they are preserved.
metadata[name] = MetadataEntry(name=name, preserve=preserve, datatype=datatype, value=value)
return metadata
def read_materials(self, root):
"""
Read out all of the material resources from the 3MF document.
The materials will be stored in `self.resource_materials` until it gets used to build the items.
:param root: The root of an XML document that may contain materials.
"""
for basematerials_item in root.iterfind("./3mf:resources/3mf:basematerials", MODEL_NAMESPACES):
try:
material_id = basematerials_item.attrib["id"]
except KeyError:
log.warning("Encountered a basematerials item without resource ID.")
continue # Need to have an ID, or no item can reference to the materials. Skip this one.
if material_id in self.resource_materials:
log.warning(f"Duplicate material ID: {material_id}")
continue
# Use a dictionary mapping indices to resources, because some indices may be skipped due to being invalid.
self.resource_materials[material_id] = {}
index = 0
# "Base" must be the stupidest name for a material resource. Oh well.
for base_item in basematerials_item.iterfind("./3mf:base", MODEL_NAMESPACES):
name = base_item.attrib.get("name", "3MF Material")
color = base_item.attrib.get("displaycolor")
if color is not None:
# Parse the color. It's a hexadecimal number indicating RGB or RGBA.
color = color.lstrip("#") # Should start with a #. We'll be lenient if it's not.
try:
color_int = int(color, 16)
# Separate out up to four bytes from this int, from right to left.
b1 = (color_int & 0x000000FF) / 255
b2 = ((color_int & 0x0000FF00) >> 8) / 255
b3 = ((color_int & 0x00FF0000) >> 16) / 255
b4 = ((color_int & 0xFF000000) >> 24) / 255
if len(color) == 6: # RGB format.
color = (b3, b2, b1, 1.0) # b1, b2 and b3 are B, G, R respectively. b4 is always 0.
else: # RGBA format, or invalid.
color = (b4, b3, b2, b1) # b1, b2, b3 and b4 are A, B, G, R respectively.
except ValueError:
log.warning(f"Invalid color for material {name} of resource {material_id}: {color}")
color = None # Don't add a color for this material.
# Input is valid. Create a resource.
self.resource_materials[material_id][index] = ResourceMaterial(name=name, color=color)
index += 1
if len(self.resource_materials[material_id]) == 0:
del self.resource_materials[material_id] # Don't leave empty material sets hanging.
def read_objects(self, root):
"""
Reads all repeatable build objects from the resources of an XML root node.
This stores them in the resource_objects field.
:param root: The root node of a 3dmodel.model XML file.
"""
for object_node in root.iterfind("./3mf:resources/3mf:object", MODEL_NAMESPACES):
try:
objectid = object_node.attrib["id"]
except KeyError:
log.warning("Object resource without ID!")
continue # ID is required, otherwise the build can't refer to it.
pid = object_node.attrib.get("pid") # Material ID.
pindex = object_node.attrib.get("pindex") # Index within a collection of materials.
material = None
if pid is not None and pindex is not None:
try:
index = int(pindex)
material = self.resource_materials[pid][index]
except KeyError:
log.warning(
f"Object with ID {objectid} refers to material collection {pid} with index {pindex}"
f"which doesn't exist.")
except ValueError:
log.warning(f"Object with ID {objectid} specifies material index {pindex}, which is not integer.")
vertices = self.read_vertices(object_node)
triangles, materials = self.read_triangles(object_node, material, pid)
components = self.read_components(object_node)
metadata = Metadata()
for metadata_node in object_node.iterfind("./3mf:metadatagroup", MODEL_NAMESPACES):
metadata = self.read_metadata(metadata_node, metadata)
if "partnumber" in object_node.attrib:
# Blender has no way to ensure that custom properties get preserved if a mesh is split up, but for most
# operations this is retained properly.
metadata["3mf:partnumber"] = MetadataEntry(
name="3mf:partnumber",
preserve=True,
datatype="xs:string",
value=object_node.attrib["partnumber"])
metadata["3mf:object_type"] = MetadataEntry(
name="3mf:object_type",
preserve=True,
datatype="xs:string",
value=object_node.attrib.get("type", "model"))
self.resource_objects[objectid] = ResourceObject(
vertices=vertices,
triangles=triangles,
materials=materials,
components=components,
metadata=metadata)
def read_vertices(self, object_node):
"""
Reads out the vertices from an XML node of an object.
If any vertex is corrupt, like with a coordinate missing or not proper floats, then the 0 coordinate will be
used. This is to prevent messing up the list of indices.
:param object_node: An <object> element from the 3dmodel.model file.
:return: List of vertices in that object. Each vertex is a tuple of 3 floats for X, Y and Z.
"""
result = []
for vertex in object_node.iterfind("./3mf:mesh/3mf:vertices/3mf:vertex", MODEL_NAMESPACES):
attrib = vertex.attrib
try:
x = float(attrib.get("x", 0))
except ValueError: # Not a float.
log.warning("Vertex missing X coordinate.")
x = 0
try:
y = float(attrib.get("y", 0))
except ValueError:
log.warning("Vertex missing Y coordinate.")
y = 0
try:
z = float(attrib.get("z", 0))
except ValueError:
log.warning("Vertex missing Z coordinate.")
z = 0
result.append((x, y, z))
return result
def read_triangles(self, object_node, default_material, material_pid):
"""
Reads out the triangles from an XML node of an object.
These triangles always consist of 3 vertices each. Each vertex is an index to the list of vertices read
previously. The triangle also contains an associated material, or None if the triangle gets no material.
:param object_node: An <object> element from the 3dmodel.model file.
:param default_material: If the triangle specifies no material, it should get this material. May be `None` if
the model specifies no material.
:param material_pid: Triangles that specify a material index will get their material from this material group.
:return: Two lists of equal length. The first lists the vertices of each triangle, which are 3-tuples of
integers referring to the first, second and third vertex of the triangle. The second list contains a material
for each triangle, or `None` if the triangle doesn't get a material.
"""
vertices = []
materials = []
for triangle in object_node.iterfind("./3mf:mesh/3mf:triangles/3mf:triangle", MODEL_NAMESPACES):
attrib = triangle.attrib
try:
v1 = int(attrib["v1"])
v2 = int(attrib["v2"])
v3 = int(attrib["v3"])
if v1 < 0 or v2 < 0 or v3 < 0: # Negative indices are not allowed.
log.warning("Triangle containing negative index to vertex list.")
continue
pid = attrib.get("pid", material_pid)
p1 = attrib.get("p1")
if p1 is None:
material = default_material
else:
try:
material = self.resource_materials[pid][int(p1)]
except KeyError as e:
# Sorry. It's hard to give an exception more specific than this.
log.warning(f"Material {e} is missing.")
material = default_material
except ValueError as e:
log.warning(f"Material index is not an integer: {e}")
material = default_material
vertices.append((v1, v2, v3))
materials.append(material)
except KeyError as e:
log.warning(f"Vertex {e} is missing.")
continue
except ValueError as e:
log.warning(f"Vertex reference is not an integer: {e}")
continue # No fallback this time. Leave out the entire triangle.
return vertices, materials
def read_components(self, object_node):
"""
Reads out the components from an XML node of an object.
These components refer to other resource objects, with a transformation applied. They will eventually appear in
the scene as sub-objects.
:param object_node: An <object> element from the 3dmodel.model file.
:return: List of components in this object node.
"""
result = []
for component_node in object_node.iterfind("./3mf:components/3mf:component", MODEL_NAMESPACES):
try:
objectid = component_node.attrib["objectid"]
except KeyError: # ID is required.
continue # Ignore this invalid component.
transform = self.parse_transformation(component_node.attrib.get("transform", ""))
result.append(Component(resource_object=objectid, transformation=transform))
return result
def parse_transformation(self, transformation_str):
"""
Parses a transformation matrix as written in the 3MF files.
Transformations in 3MF files are written in the form:
`m00 m01 m01 m10 m11 m12 m20 m21 m22 m30 m31 m32`
This would then result in a row-major matrix of the form:
```
_ _
| m00 m01 m02 0.0 |
| m10 m11 m12 0.0 |
| m20 m21 m22 0.0 |
| m30 m31 m32 1.0 |
- -
```
:param transformation_str: A transformation as represented in 3MF.
:return: A `Matrix` object with the correct transformation.
"""
components = transformation_str.split(" ")
result = mathutils.Matrix.Identity(4)
if transformation_str == "": # Early-out if transformation is missing. This is not malformed.
return result
row = -1
col = 0
for component in components:
row += 1
if row > 2:
col += 1
row = 0
if col > 3:
log.warning(f"Transformation matrix contains too many components: {transformation_str}")
break # Too many components. Ignore the rest.
try:
component_float = float(component)
except ValueError: # Not a proper float. Skip this one.
log.warning(f"Transformation matrix malformed: {transformation_str}")
continue
result[row][col] = component_float
return result
def build_items(self, root, scale_unit):
"""
Builds the scene. This places objects with certain transformations in
the scene.
:param root: The root node of the 3dmodel.model XML document.
:param scale_unit: The scale to apply for the units of the model to be
transformed to Blender's units, as a float ratio.
:return: A sequence of Blender Objects that need to be placed in the
scene. Each mesh gets transformed appropriately.
"""
for build_item in root.iterfind("./3mf:build/3mf:item", MODEL_NAMESPACES):
try:
objectid = build_item.attrib["objectid"]
resource_object = self.resource_objects[objectid]
except KeyError: # ID is required, and it must be in the available resource_objects.
log.warning("Encountered build item without object ID.")
continue # Ignore this invalid item.
metadata = Metadata()
for metadata_node in build_item.iterfind("./3mf:metadatagroup", MODEL_NAMESPACES):
metadata = self.read_metadata(metadata_node, metadata)
if "partnumber" in build_item.attrib:
metadata["3mf:partnumber"] = MetadataEntry(
name="3mf:partnumber",
preserve=True,
datatype="xs:string",
value=build_item.attrib["partnumber"])
transform = mathutils.Matrix.Scale(scale_unit, 4)
transform @= self.parse_transformation(build_item.attrib.get("transform", ""))
self.build_object(resource_object, transform, metadata, [objectid])
def build_object(self, resource_object, transformation, metadata, objectid_stack_trace, parent=None):
"""
Converts a resource object into a Blender object.
This resource object may refer to components that need to be built along. These components may again have
subcomponents, and so on. These will be built recursively. A "stack trace" will be traced in order to prevent
going into an infinite recursion.
:param resource_object: The resource object that needs to be converted.
:param transformation: A transformation matrix to apply to this resource object.
:param metadata: A collection of metadata belonging to this build item.
:param objectid_stack_trace: A list of all object IDs that have been processed so far, including the object ID
we're processing now.
:param parent: The resulting object must be marked as a child of this Blender object.
:return: A sequence of Blender objects. These objects may be "nested" in the sense that they sometimes refer to
other objects as their parents.
"""
# Create a mesh if there is mesh data here.
mesh = None
if resource_object.triangles:
mesh = bpy.data.meshes.new("3MF Mesh")
mesh.from_pydata(resource_object.vertices, [], resource_object.triangles)
mesh.update()
resource_object.metadata.store(mesh)
# Mapping resource materials to indices in the list of materials for this specific mesh.
materials_to_index = {}
for triangle_index, triangle_material in enumerate(resource_object.materials):
if triangle_material is None:
continue
# Add the material to Blender if it doesn't exist yet. Otherwise create a new material in Blender.
if triangle_material not in self.resource_to_material:
material = bpy.data.materials.new(triangle_material.name)
material.use_nodes = True
principled = bpy_extras.node_shader_utils.PrincipledBSDFWrapper(material, is_readonly=False)
principled.base_color = triangle_material.color[:3]
principled.alpha = triangle_material.color[3]
self.resource_to_material[triangle_material] = material
else:
material = self.resource_to_material[triangle_material]
# Add the material to this mesh if it doesn't have it yet. Otherwise re-use previous index.
if triangle_material not in materials_to_index:
new_index = len(mesh.materials.items())
if new_index > 32767:
log.warning("Blender doesn't support more than 32768 different materials per mesh.")
continue
mesh.materials.append(material)
materials_to_index[triangle_material] = new_index
# Assign the material to the correct triangle.
mesh.polygons[triangle_index].material_index = materials_to_index[triangle_material]
# Create an object.
blender_object = bpy.data.objects.new("3MF Object", mesh)
self.num_loaded += 1
if parent is not None:
blender_object.parent = parent
blender_object.matrix_world = transformation
bpy.context.collection.objects.link(blender_object)
bpy.context.view_layer.objects.active = blender_object
blender_object.select_set(True)
metadata.store(blender_object)
if "3mf:object_type" in resource_object.metadata\
and resource_object.metadata["3mf:object_type"].value in {"solidsupport", "support"}:
# Don't render support meshes.
blender_object.hide_render = True
# Recurse for all components.
for component in resource_object.components:
if component.resource_object in objectid_stack_trace:
# These object IDs refer to each other in a loop. Don't go in there!
log.warning(f"Recursive components in object ID: {component.resource_object}")
continue
try:
child_object = self.resource_objects[component.resource_object]
except KeyError: # Invalid resource ID. Doesn't exist!
log.warning(f"Build item with unknown resource ID: {component.resource_object}")
continue
transform = transformation @ component.transformation # Apply the child's transformation and pass it on.
objectid_stack_trace.append(component.resource_object)
self.build_object(child_object, transform, metadata, objectid_stack_trace, parent=blender_object)
objectid_stack_trace.pop()

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io_mesh_3mf/metadata.py Normal file
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@ -0,0 +1,198 @@
# Blender add-on to import and export 3MF files.
# Copyright (C) 2020 Ghostkeeper
# This add-on is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
# Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
# later version.
# This add-on is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for
# details.
# You should have received a copy of the GNU Affero General Public License along with this plug-in. If not, see
# <https://gnu.org/licenses/>.
# <pep8 compliant>
import collections # For named tuples.
import idprop.types # To interpret property groups as metadata entries.
MetadataEntry = collections.namedtuple("MetadataEntry", ["name", "preserve", "datatype", "value"])
class Metadata:
"""
This class tracks the metadata of a Blender object.
You can use it to update the metadata when importing, or to get the scene's metadata when exporting. It has a
routine to store the metadata in a Blender object and to retrieve it from that Blender object again.
This class functions like a temporary data structure only. It is blissfully unaware of the intricacies of the 3MF
file format specifically, save for knowing all of the properties of a metadata entry that can be specified.
The class' signature is like a dictionary. The keys of the dictionary are the names of the metadata entries. The
values of the dictionary are MetadataEntry named tuples, containing several properties of the metadata entries as
can be specified in the 3MF format. However the behaviour of the class is not entirely like a dictionary, since this
dictionary will only store metadata that is consistent across all of the attempts to store metadata. If you store
the same metadata entry multiple times, it will store only one copy, which is like a dictionary. However if you
store an entry with the same name but a different value, it'll know that the metadata is inconsistent across the
different files and thus will pretend that this metadata entry was not set. This way, if you load multiple 3MF files
into one scene in Blender, you will only get the intersection of the matching metadata entries.
"""
def __init__(self):
"""
Create an empty storage of metadata.
"""
self.metadata = {}
def __setitem__(self, key, value):
"""
Add a metadata entry to this storage.
:param key: The name of the entry.
:param value: A `MetadataEntry` object to store.
"""
if key not in self.metadata:
# Completely new value. We can just store this one, since it's always consistent with existing metadata.
self.metadata[key] = value
return
if self.metadata[key] is None:
# This entry was already in conflict with another entry and erased.
# The new value will also be in conflict with at least one, so should also not be stored.
return
competing = self.metadata[key]
if value.value != competing.value or value.datatype != competing.datatype:
# These two are inconsistent. Erase both!
self.metadata[key] = None
return
# The two are consistent. Usually no need to store anything, since it's already stored.
# The "preserve" property may be different. Preserve if any of them says to preserve.
if not competing.preserve and value.preserve: # Prevent unnecessary construction of namedtuples.
self.metadata[key] = MetadataEntry(
name=key,
preserve=True,
datatype=competing.datatype,
value=competing.value)
def __getitem__(self, key):
"""
Retrieves a metadata entry, if it exists and was not in conflict.
:param key: The name of the metadata entry to get.
:return: The `MetadataEntry` object stored there.
:raises: `KeyError` if there is no metadata entry or it was in conflict.
"""
if key not in self.metadata or self.metadata[key] is None:
# Metadata entry doesn't exist, or its values are conflicting with each other across multiple files.
raise KeyError(key)
return self.metadata[key]
def __contains__(self, item):
"""
Tests if a metadata entry with a certain name is present and not in conflict.
:param item: The name of the metadata entry to test for.
:return: `True` if the metadata entry is present and not in conflict, or `False` if it's not present or in
conflict with metadata values from multiple files.
"""
return item in self.metadata and self.metadata[item] is not None
def __bool__(self):
"""
Checks if there is any content in this metadata storage.
Conflicting metadata entries are not counted as content in this case.
:return: `True` if there is metadata in this storage, or `False` if there isn't any.
"""
return any(self.values())
def __len__(self):
"""
Returns the number of valid items in this metadata storage.
An item is only valid if it's not in conflict, i.e. if it would be present in an iteration over the storage.
:return: The number of valid metadata entries.
"""
return sum(1 for _ in self.values())
def __delitem__(self, key):
"""
Completely delete all traces of a metadata entry from this storage.
Even if there was no real entry, but the shadow of entries being in conflict, that information will be removed.
That way it'll allow for a new value to be stored.
Contrary to the normal dictionary's version, this one does check for the key's existence, so you don't need to
do that manually.
"""
if key in self.metadata:
del self.metadata[key]
def __eq__(self, other):
"""
Compares two metadata groups together.
This is currently just used for the unit tests to see if the metadata is constructed correctly.
:param other: The metadata object to compare to.
:return: `True` if the two groups of metadata contain the same metadata (including which entries are in
conflict), or `False` otherwise.
"""
return self.metadata == other.metadata
def store(self, blender_object):
"""
Store this metadata in a Blender object.
The metadata will be stored as Blender properties. In the case of properties known to Blender they will be
translated appropriately.
:param blender_object: The Blender object to store the metadata in.
"""
for metadata_entry in self.values():
name = metadata_entry.name
value = metadata_entry.value
if name == "Title": # Has a built-in ID property for objects as well as scenes.
blender_object.name = value
elif name == "3mf:partnumber":
# Special case: This is always a string and doesn't need the preserve attribute. We can simplify this to
# make it easier to edit.
blender_object[name] = value
else:
blender_object[name] = {
"datatype": metadata_entry.datatype,
"preserve": metadata_entry.preserve,
"value": value,
}
def retrieve(self, blender_object):
"""
Retrieve metadata from a Blender object.
The metadata will get stored in this existing instance.
The metadata from the Blender object will get merged with the data that already exists in this instance. In case
of conflicting metadata values, those metadata entries will be left out.
:param blender_object: A Blender object to retrieve metadata from.
"""
for key in blender_object.keys():
entry = blender_object[key]
if key == "3mf:partnumber":
self[key] = MetadataEntry(name=key, preserve=True, datatype="xs:string", value=entry)
continue
if isinstance(entry, idprop.types.IDPropertyGroup)\
and "datatype" in entry.keys()\
and "preserve" in entry.keys()\
and "value" in entry.keys(): # Most likely a metadata entry from a previous 3MF file.
self[key] = MetadataEntry(
name=key,
preserve=entry.get("preserve"),
datatype=entry.get("datatype"),
value=entry.get("value"))
# Don't mess with metadata added by the user or their other Blender add-ons. Don't want to break their
# behaviour.
self["Title"] = MetadataEntry(name="Title", preserve=True, datatype="xs:string", value=blender_object.name)
def values(self):
"""
Return all metadata entries that are registered in this storage and not in conflict.
:return: A generator of metadata entries.
"""
yield from filter(lambda entry: entry is not None, self.metadata.values())

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io_mesh_3mf/unit_conversions.py Normal file
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# Blender add-on to import and export 3MF files.
# Copyright (C) 2020 Ghostkeeper
# This add-on is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
# Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
# later version.
# This add-on is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for
# details.
# You should have received a copy of the GNU Affero General Public License along with this plug-in. If not, see
# <https://gnu.org/licenses/>.
# <pep8 compliant>
"""
This file defines unit conversions between Blender's units and 3MF's units.
"""
blender_to_metre = { # Scale of each of Blender's length units to a metre.
'THOU': 0.0000254,
'INCHES': 0.0254,
'FEET': 0.3048,
'YARDS': 0.9144,
'CHAINS': 20.1168,
'FURLONGS': 201.168,
'MILES': 1609.344,
'MICROMETERS': 0.000001,
'MILLIMETERS': 0.001,
'CENTIMETERS': 0.01,
'DECIMETERS': 0.1,
'METERS': 1,
'ADAPTIVE': 1,
'DEKAMETERS': 10,
'HECTOMETERS': 100,
'KILOMETERS': 1000
}
threemf_to_metre = { # Scale of each of 3MF's length units to a metre.
'micron': 0.000001,
'millimeter': 0.001,
'centimeter': 0.01,
'inch': 0.0254,
'foot': 0.3048,
'meter': 1
}