blender/blender-addons
19
43
Fork 96
Code Issues 631 Pull Requests 27 Projects 1 Releases Wiki Activity

Object.to_mesh(preserve_all_data_layers=True,...) causes strange stateful-behavior in exporters #72581

New Issue
Closed
opened 2019-12-19 18:43:11 +01:00 by Ted Greene · 9 comments
Ted Greene commented 2019-12-19 18:43:11 +01:00
Copy Link

System Information
Operating system: Tested Windows 10, x64, various Mac OS versions
Graphics card:

Blender Version
Tested: Blender 2.80-2.82a2

Short description of error
I am not sure if this is a bug or me not understanding this API. I am the maintainer of XPlane2Blender, an exporter for our flight sim's own 3D format. My users noticed that exported geometry can sometimes shift or rotate (and other weird side-effects, such as the Blender Object itself having moved after export) after each time hitting export. The common theme we found was that things with Scale transformations and modifiers on the objects seemed to trigger it. The fix is to either restart Blender or Apply All Transformations to all objects and bones.

I tracked this issue down to one parameter of in my call to Object.to_mesh: if preserve_all_data_layers is set to False these problems (as far as I've seen) go away.

I am very confused by this. I thought this API (depsgraph_get, evaluated_get, to_mesh, to_mesh_clear) was all read only and any side effects would only be applied to the temporary mesh from to_mesh.

  1. Is this a bug then or does "preserving_all_data_layers" also mean making some stateful-ness.
  2. I would also like to know what exact data layers get dropped when preserving_all_data_layers is set to False.

Exact steps for others to reproduce the error

  1. Unless you really want to install and use the addon, I've provided the outputted files (look at how the VT entries change) and a screenshot

export_multiple_times_result.png

export_multiple_times_result.blend

test_multiple_export_works3.obj

test_multiple_export_works6.obj

test_multiple_export_works9.obj

  1. The relevant code is in a file called xplane_mesh.py, lines 60-63 and 136. See on github (https://github.com/X-Plane/XPlane2Blender/blob/399-blender-28-support/io_xplane2blender/xplane_types/xplane_mesh.py)
**System Information** Operating system: Tested Windows 10, x64, various Mac OS versions Graphics card: **Blender Version** Tested: Blender 2.80-2.82a2 **Short description of error** I am not sure if this is a bug or me not understanding this API. I am the maintainer of XPlane2Blender, an exporter for our flight sim's own 3D format. My users noticed that exported geometry can sometimes shift or rotate (and other weird side-effects, such as the Blender Object itself having moved after export) after each time hitting export. The common theme we found was that things with Scale transformations and modifiers on the objects seemed to trigger it. The fix is to either restart Blender or Apply All Transformations to all objects and bones. I tracked this issue down to one parameter of in my call to Object.to_mesh: if preserve_all_data_layers is set to False these problems (as far as I've seen) go away. I am very confused by this. I thought this API (depsgraph_get, evaluated_get, to_mesh, to_mesh_clear) was all read only and any side effects would only be applied to the temporary mesh from to_mesh. 1. Is this a bug then or does "preserving_all_data_layers" also mean making some stateful-ness. 2. I would also like to know what exact data layers get dropped when preserving_all_data_layers is set to False. **Exact steps for others to reproduce the error** 1. Unless you really want to install and use the addon, I've provided the outputted files (look at how the VT entries change) and a screenshot ![export_multiple_times_result.png](https://archive.blender.org/developer/F8234793/export_multiple_times_result.png) [export_multiple_times_result.blend](https://archive.blender.org/developer/F8234791/export_multiple_times_result.blend) [test_multiple_export_works3.obj](https://archive.blender.org/developer/F8234788/test_multiple_export_works3.obj) [test_multiple_export_works6.obj](https://archive.blender.org/developer/F8234789/test_multiple_export_works6.obj) [test_multiple_export_works9.obj](https://archive.blender.org/developer/F8234790/test_multiple_export_works9.obj) 2. The relevant code is in a file called xplane_mesh.py, lines 60-63 and 136. See on github (https://github.com/X-Plane/XPlane2Blender/blob/399-blender-28-support/io_xplane2blender/xplane_types/xplane_mesh.py)
Ted Greene commented 2019-12-19 18:43:11 +01:00
Author
Copy Link

Added subscriber: @tngreene

Added subscriber: @tngreene
Jacques Lucke commented 2019-12-28 15:30:10 +01:00
Member
Copy Link

Added subscriber: @JacquesLucke

Added subscriber: @JacquesLucke
Jacques Lucke commented 2019-12-28 15:30:10 +01:00
Member
Copy Link

Changed status from 'Needs Triage' to: 'Needs User Info'

Changed status from 'Needs Triage' to: 'Needs User Info'
Jacques Lucke commented 2019-12-28 15:30:10 +01:00
Member
Copy Link

Are you able to reproduce this issue outside of your addon in a simple standalone script? That would make debugging the issue much easier.

Are you able to reproduce this issue outside of your addon in a simple standalone script? That would make debugging the issue much easier.
Philipp Oeser commented 2020-01-07 10:09:34 +01:00
Member
Copy Link

Added subscriber: @lichtwerk

Added subscriber: @lichtwerk
Philipp Oeser commented 2020-01-07 10:09:34 +01:00
Member
Copy Link

Changed status from 'Needs User Info' to: 'Archived'

Changed status from 'Needs User Info' to: 'Archived'
Philipp Oeser self-assigned this 2020-01-07 10:09:34 +01:00
Philipp Oeser commented 2020-01-07 10:09:34 +01:00
Member
Copy Link

More than a week without reply or activity. Due to the policy of the tracker closing for until required info/data are provided.

More than a week without reply or activity. Due to the policy of the tracker closing for until required info/data are provided.
Daniel Bauer commented 2020-07-27 22:09:26 +02:00
Copy Link

Added subscriber: @skatbude

Added subscriber: @skatbude
Daniel Bauer commented 2020-07-27 22:09:26 +02:00
Copy Link

System Information
Operating system: Linux-5.7.2-sparky-amd64-x86_64-with-glibc2.29 64 Bits
Graphics card: Mesa DRI Intel(R) HD Graphics 3000 (SNB GT2) Intel Open Source Technology Center 3.3 (Core Profile) Mesa 20.1.2

Blender Version
Broken: version: 2.83.2
Worked: -

Short description of error
I stumbled across the same issue while modifying the .obj-exporter.
The issue seems to be related to both
object.evaluated_get(depsgraph)
and
obj.to_mesh(preserve_all_data_layers=True, depsgraph=depsgraph)

The attached file contains a cube that is scaled by factor 2.
A custom Operator uses above code to retrieve the cube's mesh and then transform it by the cubes world matrix.
Next the coordinate of one Vertex is reported to Info.
Expected Result: (2, 2, 2) (modulo sign)
Actual Result: Coordinates double every time the Operator is executed.

Exact steps for others to reproduce the error
Open the attached .blend file and follow the instruction on screen (Readme file is included).
statefulBehaviour.blend

**System Information** Operating system: Linux-5.7.2-sparky-amd64-x86_64-with-glibc2.29 64 Bits Graphics card: Mesa DRI Intel(R) HD Graphics 3000 (SNB GT2) Intel Open Source Technology Center 3.3 (Core Profile) Mesa 20.1.2 **Blender Version** Broken: version: 2.83.2 Worked: - **Short description of error** I stumbled across the same issue while modifying the .obj-exporter. The issue seems to be related to both ```object.evaluated_get(depsgraph)``` and ```obj.to_mesh(preserve_all_data_layers=True, depsgraph=depsgraph)``` The attached file contains a cube that is scaled by factor 2. A custom Operator uses above code to retrieve the cube's mesh and then transform it by the cubes world matrix. Next the coordinate of one Vertex is reported to Info. __Expected Result:__ (2, 2, 2) (modulo sign) __Actual Result:__ Coordinates double every time the Operator is executed. **Exact steps for others to reproduce the error** Open the attached .blend file and follow the instruction on screen (Readme file is included). [statefulBehaviour.blend](https://archive.blender.org/developer/F8723611/statefulBehaviour.blend)
Sign in to join this conversation.
No Branch/Tag Specified
Branches Tags
Labels
Clear labels   
Interest
Animation & Rigging

  
Interest
Blender Cloud

  
Interest
Collada

  
Interest
Core

  
Interest
Documentation

  
Interest
Eevee & Viewport

  
Interest
Geometry Nodes

  
Interest
Grease Pencil

  
Interest
Import and Export

  
Interest
Modeling

  
Interest
Modifiers

  
Interest
Nodes & Physics

  
Interest
Pipeline, Assets & IO

  
Interest
Platforms, Builds, Tests & Devices

  
Interest
Python API

  
Interest
Rendering & Cycles

  
Interest
Sculpt, Paint & Texture

  
Interest
Translations

  
Interest
User Interface

  
Interest
UV Editing

  
Interest
VFX & Video

  
Meta
Good First Issue

  
Meta
Papercut

  
Module
Add-ons (BF-Blender)

  
Module
Add-ons (Community)

  
Platform
Linux

  
Platform
macOS

  
Platform
Windows

  
Priority
High

  
Priority
Low

  
Priority
Normal

  
Priority
Unbreak Now!

  
Status
Archived

  
Status
Confirmed

  
Status
Duplicate

  
Status
Needs Info from Developers

  
Status
Needs Information from User

  
Status
Needs Triage

  
Status
Resolved

  
Type
Bug

  
Type
Design

  
Type
Known Issue

  
Type
Patch

  
Type
Report

  
Type
To Do

No Label
Interest
Animation & Rigging
Interest
Blender Cloud
Interest
Collada
Interest
Core
Interest
Documentation
Interest
Eevee & Viewport
Interest
Geometry Nodes
Interest
Grease Pencil
Interest
Import and Export
Interest
Modeling
Interest
Modifiers
Interest
Nodes & Physics
Interest
Pipeline, Assets & IO
Interest
Platforms, Builds, Tests & Devices
Interest
Python API
Interest
Rendering & Cycles
Interest
Sculpt, Paint & Texture
Interest
Translations
Interest
User Interface
Interest
UV Editing
Interest
VFX & Video
Meta
Good First Issue
Meta
Papercut
Module
Add-ons (BF-Blender)
Module
Add-ons (Community)
Platform
Linux
Platform
macOS
Platform
Windows
Priority
High
Priority
Low
Priority
Normal
Priority
Unbreak Now!
Status
Archived
Status
Confirmed
Status
Duplicate
Status
Needs Info from Developers
Status
Needs Information from User
Status
Needs Triage
Status
Resolved
Type
Bug
Type
Design
Type
Known Issue
Type
Patch
Type
Report
Type
To Do
Milestone
Clear milestone
No items
No Milestone
Projects
Clear projects
No project
Assignees
Clear assignees
No Assignees
Philipp Oeser
4 Participants
Notifications
Due Date
The due date is invalid or out of range. Please use the format 'yyyy-mm-dd'.

No due date set.

Dependencies

No dependencies set.

Reference: blender/blender-addons#72581
No description provided.
Delete Branch "%!s()"

Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?