Export: Different transform value of Leaf bone #112312

New Issue

Jpzhao · 2023-09-13T05:26:03+02:00

Jpzhao commented

2023-09-13 05:26:03 +02:00

System Information
Operating system: Windows 11
Graphics card: NVIDIA GeForce MX550

Blender Version
Broken: 3.4, 4.0
Worked: Don't know

Short description of error
Wrong coordinates of "head_tail" after importing the gltf file

Steps to Reproduce

Open attached file, export in gltf format
Import back the armature, notice the difference

Original report

**Short description of error**

I get the wrong result when using bpy library to move bones. More specifically, the coordinates of "head_tail" in my code shown in the first picture is not the same as the result shown in the second picture.

Exact steps for others to reproduce the error

download the .glb file
run the code below (code and .glb file should be in the same folder, note that the python version is 3.10.8 and bpy==3.4.0, numpy==1.23.2.)
open the generated file "test.glb" in blender.

code:

import bpy

class RiggingHelper(object):
    def __init__(self, armature_name):
        self.armature = bpy.data.objects[armature_name] # obArm
    
    # bone select function
    def select_bones_edit(self, bones_to_select, head=False, tail=False, body=False):
        # edit mode select bones
        # bones_to_select: list []
        bpy.ops.armature.select_all(action='DESELECT')
        for bone_name in bones_to_select:
            if head:
                self.armature.data.edit_bones[bone_name].select_head = True
            if tail:
                self.armature.data.edit_bones[bone_name].select_tail = True
            if body:
                self.armature.data.edit_bones[bone_name].select= True

    def active_bone_edit(self, bone_name):
        # edit mode
        self.armature.data.edit_bones.active = self.armature.data.edit_bones[bone_name]

    def rename_bone(self, ori_name, new_name):
        self.active_bone_edit(ori_name)
        bpy.context.active_bone.name = new_name

    def move_bone(self, bone_name, head_position, tail_position):
        # head_position and tail_position are three dimensitional tuple
        self.active_bone_edit(bone_name)
        self.armature.data.edit_bones[bone_name].head = head_position
        self.armature.data.edit_bones[bone_name].tail = tail_position

    def set_mode(self, mode='OBJECT'):
        # mode should be Capitalized
        bpy.ops.object.mode_set(mode=mode)
             
    def extrude_bone_edit(self, ori_bone_name, position, x=0, y=0, z=0):
        # position: 'head' or 'tail'
        if position == 'head':
            self.select_bones_edit([ori_bone_name], head=True)
        elif position == 'tail':
            self.select_bones_edit([ori_bone_name], tail=True)
        bpy.ops.armature.extrude_move(TRANSFORM_OT_translate={"value":(x, y, z)}) # deafult original position 

    def clear_parent_edit(self, bones_name_list, type='CLEAR'):
        # type, "CLEAR" or "DISCONNECT", default "CLEAR"
        # clear parent relationship
        self.select_bones_edit(bones_name_list, 
                        head=True, tail=True, body=True)
        bpy.ops.armature.parent_clear(type=type)

hip_head = (0.0060, -0.0106, 0.9484)
hip_tail = (0.0059, -0.0160, 1.0179)
spine_head = (0.0059, -0.0160, 1.0179)
spine_tail = (0.0059, -0.0213, 1.1300)
chest_head = (0.0059, -0.0213, 1.1300)
chest_tail = (0.0060, 0.0324, 1.4304)
neck_head = (0.0060, 0.0324, 1.4304)
neck_tail = (0.0061, 0.0581, 1.5430)
head_head = (0.0061, 0.0581, 1.5430)
head_tail = (0.0061, 0.0457, 1.7155)

bpy.ops.object.select_all(action='SELECT')
bpy.ops.object.delete(use_global=False)
# import model
bpy.ops.import_scene.gltf(filepath="A0920230720170849.glb")
bpy.ops.object.armature_add()
helper = RiggingHelper('Armature')
obArm = bpy.data.objects['Armature']
bpy.context.view_layer.objects.active = obArm #
helper.set_mode('EDIT')
helper.rename_bone('Bone', 'Root')
helper.move_bone('Root', (0,0,0), (0, 0.3,0))
## 1.2 add spine bones--------
# extrude another bone from the root bone
helper.extrude_bone_edit('Root', 'head')
helper.rename_bone('Root.001', 'Hip')
helper.clear_parent_edit(['Hip'])

helper.extrude_bone_edit('Hip', 'tail')
helper.rename_bone('Hip.001', 'Spine')

helper.extrude_bone_edit('Spine', 'tail')
helper.rename_bone('Spine.001', 'Chest')

helper.extrude_bone_edit('Chest', 'tail')
helper.rename_bone('Chest.001', 'Neck')

helper.extrude_bone_edit('Neck', 'tail')
helper.rename_bone('Neck.001', 'Head')

# move & scale bones from hip to head
helper.move_bone('Hip', hip_head, hip_tail)
helper.move_bone('Spine', spine_head, spine_tail)
helper.move_bone('Chest', chest_head, chest_tail)
helper.move_bone('Neck', neck_head, neck_tail)
helper.move_bone('Head', head_head, head_tail)
bpy.ops.export_scene.gltf(filepath='test.glb')

**System Information** Operating system: Windows 11 Graphics card: NVIDIA GeForce MX550 **Blender Version** Broken: 3.4, 4.0 Worked: Don't know **Short description of error** Wrong coordinates of "head_tail" after importing the gltf file **Steps to Reproduce** - [Open attached file](https://projects.blender.org/attachments/50a7e6a1-10e5-472c-96d0-5b4674df5799), export in gltf format - Import back the armature, notice the difference <details> <summary> Original report </summary> **Short description of error** I get the wrong result when using bpy library to move bones. More specifically, the coordinates of "head_tail" in my code shown in the first picture is not the same as the result shown in the second picture. ![image](/attachments/bcd0c0f0-0781-4f5c-9cc2-0926bfd59de3) ![image](/attachments/5281e798-14d6-4180-a5ea-b61454e44fe9) **Exact steps for others to reproduce the error** 1. download the .glb file 2. run the code below (code and .glb file should be in the same folder, note that the python version is 3.10.8 and bpy==3.4.0, numpy==1.23.2.) 3. open the generated file "test.glb" in blender. code: ``` import bpy class RiggingHelper(object): def __init__(self, armature_name): self.armature = bpy.data.objects[armature_name] # obArm # bone select function def select_bones_edit(self, bones_to_select, head=False, tail=False, body=False): # edit mode select bones # bones_to_select: list [] bpy.ops.armature.select_all(action='DESELECT') for bone_name in bones_to_select: if head: self.armature.data.edit_bones[bone_name].select_head = True if tail: self.armature.data.edit_bones[bone_name].select_tail = True if body: self.armature.data.edit_bones[bone_name].select= True def active_bone_edit(self, bone_name): # edit mode self.armature.data.edit_bones.active = self.armature.data.edit_bones[bone_name] def rename_bone(self, ori_name, new_name): self.active_bone_edit(ori_name) bpy.context.active_bone.name = new_name def move_bone(self, bone_name, head_position, tail_position): # head_position and tail_position are three dimensitional tuple self.active_bone_edit(bone_name) self.armature.data.edit_bones[bone_name].head = head_position self.armature.data.edit_bones[bone_name].tail = tail_position def set_mode(self, mode='OBJECT'): # mode should be Capitalized bpy.ops.object.mode_set(mode=mode) def extrude_bone_edit(self, ori_bone_name, position, x=0, y=0, z=0): # position: 'head' or 'tail' if position == 'head': self.select_bones_edit([ori_bone_name], head=True) elif position == 'tail': self.select_bones_edit([ori_bone_name], tail=True) bpy.ops.armature.extrude_move(TRANSFORM_OT_translate={"value":(x, y, z)}) # deafult original position def clear_parent_edit(self, bones_name_list, type='CLEAR'): # type, "CLEAR" or "DISCONNECT", default "CLEAR" # clear parent relationship self.select_bones_edit(bones_name_list, head=True, tail=True, body=True) bpy.ops.armature.parent_clear(type=type) hip_head = (0.0060, -0.0106, 0.9484) hip_tail = (0.0059, -0.0160, 1.0179) spine_head = (0.0059, -0.0160, 1.0179) spine_tail = (0.0059, -0.0213, 1.1300) chest_head = (0.0059, -0.0213, 1.1300) chest_tail = (0.0060, 0.0324, 1.4304) neck_head = (0.0060, 0.0324, 1.4304) neck_tail = (0.0061, 0.0581, 1.5430) head_head = (0.0061, 0.0581, 1.5430) head_tail = (0.0061, 0.0457, 1.7155) bpy.ops.object.select_all(action='SELECT') bpy.ops.object.delete(use_global=False) # import model bpy.ops.import_scene.gltf(filepath="A0920230720170849.glb") bpy.ops.object.armature_add() helper = RiggingHelper('Armature') obArm = bpy.data.objects['Armature'] bpy.context.view_layer.objects.active = obArm # helper.set_mode('EDIT') helper.rename_bone('Bone', 'Root') helper.move_bone('Root', (0,0,0), (0, 0.3,0)) ## 1.2 add spine bones-------- # extrude another bone from the root bone helper.extrude_bone_edit('Root', 'head') helper.rename_bone('Root.001', 'Hip') helper.clear_parent_edit(['Hip']) helper.extrude_bone_edit('Hip', 'tail') helper.rename_bone('Hip.001', 'Spine') helper.extrude_bone_edit('Spine', 'tail') helper.rename_bone('Spine.001', 'Chest') helper.extrude_bone_edit('Chest', 'tail') helper.rename_bone('Chest.001', 'Neck') helper.extrude_bone_edit('Neck', 'tail') helper.rename_bone('Neck.001', 'Head') # move & scale bones from hip to head helper.move_bone('Hip', hip_head, hip_tail) helper.move_bone('Spine', spine_head, spine_tail) helper.move_bone('Chest', chest_head, chest_tail) helper.move_bone('Neck', neck_head, neck_tail) helper.move_bone('Head', head_head, head_tail) bpy.ops.export_scene.gltf(filepath='test.glb') ``` </details>

image.png

100 KiB

image.png

540 KiB

A0920230720170849.glb

4.4 MiB

Jpzhao added the

labels 2023-09-13 05:26:03 +02:00

Pratik Borhade commented

2023-09-13 12:01:40 +02:00

Hi, thanks for the report. Script actually generate and translate bones to defined location but gltf export has affected the transform. I might have missed something here, will check again.

Pratik Borhade commented

2023-09-13 12:31:53 +02:00

@JulienDuroure hi, is this a known behavior with bones/armatures?
I can confirm this with FBX export to. But this is avoidable there with add leaf bone property.

Open attached file and export in gltf format
Import back the armature and notice the difference

@JulienDuroure hi, is this a known behavior with bones/armatures? I can confirm this with FBX export to. But this is avoidable there with `add leaf bone` property. - - - - Open attached file and export in gltf format - Import back the armature and notice the difference

112312.blend

3.1 MiB

Pratik Borhade added

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Export: Different transform value of Leaf bone #112312