Collada export "Global Orientation" setting does not work properly for child nodes #69491

New Issue

kaalus · 2019-09-04T14:44:53+02:00

kaalus commented

2019-09-04 14:44:53 +02:00

System Information
Operating system: Windows-10-10.0.17763 64 Bits
Graphics card: GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 416.81

Blender Version
Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-29 14:47, hash: f6cb5f5449
Worked: (optional)

Short description of error
Collada export "Global Orientation" setting does not work properly for child nodes.
Global orientation transformation should only be applied to root nodes, but it is applied to child nodes as well, causing corruption of hierarchical objects.
For example assume you have a tank chassis mesh with a turret mesh attached to it. We want to export it using Global Orientation setting to re-orient the axes for a game engine. If we do so, the chassis object will be correctly re-oriented. However, also the turret object will be re-oriented by the exporter, causing the turret to be rotated relative to the chassis.
Child nodes should not be re-oriented by the "Global Orientation" setting. Only root nodes should be affected.

Exact steps for others to reproduce the error

Add any two objects (cubes will do) and make one the parent of the other. Leave their transformations blank (identity) to better see the result later on.
Export this simple scene as Collada format. Change "Global Orientation" from the default setting to any custom value (for example -Z forward and Y up will do).
Look at the node transformations inside the exported .dae file. You will notice that both the root and the child node has been re-oriented by "Global Orientation" setting. The transformation of child object is no longer an identity matrix.
The exported scene is now corrupt. The child object is wrongly rotated relative to the parent.

**System Information** Operating system: Windows-10-10.0.17763 64 Bits Graphics card: GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 416.81 **Blender Version** Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-29 14:47, hash: `f6cb5f5449` Worked: (optional) **Short description of error** Collada export "Global Orientation" setting does not work properly for child nodes. Global orientation transformation should only be applied to root nodes, but it is applied to child nodes as well, causing corruption of hierarchical objects. For example assume you have a tank chassis mesh with a turret mesh attached to it. We want to export it using Global Orientation setting to re-orient the axes for a game engine. If we do so, the chassis object will be correctly re-oriented. However, also the turret object will be re-oriented by the exporter, causing the turret to be rotated relative to the chassis. Child nodes should not be re-oriented by the "Global Orientation" setting. Only root nodes should be affected. **Exact steps for others to reproduce the error** 1. Add any two objects (cubes will do) and make one the parent of the other. Leave their transformations blank (identity) to better see the result later on. 2. Export this simple scene as Collada format. Change "Global Orientation" from the default setting to any custom value (for example -Z forward and Y up will do). 3. Look at the node transformations inside the exported .dae file. You will notice that both the root and the child node has been re-oriented by "Global Orientation" setting. The transformation of child object is no longer an identity matrix. The exported scene is now corrupt. The child object is wrongly rotated relative to the parent.

kaalus commented

2019-09-04 14:44:53 +02:00

Added subscriber: @kaalus

Jacques Lucke commented

2020-01-21 15:08:57 +01:00

Added subscriber: @JacquesLucke

Jacques Lucke commented

2020-01-21 15:08:57 +01:00

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

Jacques Lucke commented

2020-01-21 15:08:57 +01:00

Thanks for the report.

Please prepare a simple .blend file that allows us to reproduce this issue more easily. This way everyone is on the same page about what the issue is.

It would also help if you could describe more exactly what you see in the file and what you would expect (for those who don't really know the Collada format).

Thanks for the report. Please prepare a simple .blend file that allows us to reproduce this issue more easily. This way everyone is on the same page about what the issue is. It would also help if you could describe more exactly what you see in the file and what you would expect (for those who don't really know the Collada format).

Dalai Felinto commented

2020-02-06 15:46:24 +01:00

Added subscriber: @dfelinto

Dalai Felinto commented

2020-02-06 15:46:24 +01:00

Keeping this open for another week since we took so long to start triaging it. But anyone feels free to close it in case of no reply if another week goes by.

kaalus commented

2020-02-07 14:38:06 +01:00

Attaching .blend file demonstrating the issue:

ExportOrientationTestCase.blend

The blend file contains two cones side by side, one a parent of the other:

To demonstrate the problem, export the scene to collada format. In the export settings, change Global Orientation setting to "Z Forward" and "Y Up".
The exporter will produce a .dae file. Now start from a blank scene and import the .dae file. This is the result:

You will notice that the relative orientation of the cones has changed. The child cone is no longer pointing in the same direction as the parent cone. If this was a complex model with many parts, it would now be completely mangled.

What is the expected outcome: the cones stay in the same relative orientation.

What causes the problem: The "Global Orientation" setting of the exporter should only be changing orientation of root objects. Child objects should be left unchanged. They are already affected by their parents' orientation. As it stands, they are transformed twice: first by the "global orientation" setting on export, second by their parent orientation, which was also transformed by the same "global orientation" setting.

Attaching .blend file demonstrating the issue: [ExportOrientationTestCase.blend](https://archive.blender.org/developer/F8327572/ExportOrientationTestCase.blend) The blend file contains two cones side by side, one a parent of the other: ![image.png](https://archive.blender.org/developer/F8327580/image.png) To demonstrate the problem, export the scene to collada format. In the export settings, change Global Orientation setting to "Z Forward" and "Y Up". The exporter will produce a .dae file. Now start from a blank scene and import the .dae file. This is the result: ![image.png](https://archive.blender.org/developer/F8327578/image.png) You will notice that the relative orientation of the cones has changed. The child cone is no longer pointing in the same direction as the parent cone. If this was a complex model with many parts, it would now be completely mangled. **What is the expected outcome**: the cones stay in the same relative orientation. **What causes the problem**: The "Global Orientation" setting of the exporter should only be changing orientation of root objects. Child objects should be left unchanged. They are already affected by their parents' orientation. As it stands, they are transformed twice: first by the "global orientation" setting on export, second by their parent orientation, which was also transformed by the same "global orientation" setting.

Jacques Lucke commented

2020-02-12 15:47:50 +01:00

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

Jacques Lucke commented

2020-02-12 15:47:50 +01:00

I can reproduce the behavior in you screenshots. It is unexpected indeed.

Bloop Trangle commented

2021-07-30 09:19:13 +02:00

Added subscriber: @Bloop

Philipp Oeser removed the

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Collada export "Global Orientation" setting does not work properly for child nodes #69491