FBX Importer, transparency of principled is connected to incorrect color (not alpha) output #85234

New Issue

Ralf Schwarz · 2021-01-30T19:36:25+01:00

Ralf Schwarz commented

2021-01-30 19:36:25 +01:00

System Information
Operating system: ubuntu linux 18.04
Graphics card: nvidia gtx 1070 ti

Blender Version
Broken: all versions since 2.79 (or when principled shader was used first in fbx import, also 2.91)

Short description of error
Export and import an object with diffuse texture including transparency. When imported the output of the diffuse texture (color) is plugged into alpha of the principled. Must be alpha to alpha.

Exact steps for others to reproduce the error
see description. Easy to reproduce by exporting and re-importing the object. Normally not a big deal, I guess. I would have fixed it, but I am not familiar with bpy.extras node_shader_utils ..

**System Information** Operating system: ubuntu linux 18.04 Graphics card: nvidia gtx 1070 ti **Blender Version** Broken: all versions since 2.79 (or when principled shader was used first in fbx import, also 2.91) **Short description of error** Export and import an object with diffuse texture including transparency. When imported the output of the diffuse texture (color) is plugged into alpha of the principled. Must be alpha to alpha. **Exact steps for others to reproduce the error** see description. Easy to reproduce by exporting and re-importing the object. Normally not a big deal, I guess. I would have fixed it, but I am not familiar with bpy.extras node_shader_utils ..

Ralf Schwarz commented

2021-01-30 19:36:25 +01:00

Added subscriber: @black-punkduck

Philipp Oeser commented

2021-02-01 10:49:18 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2021-02-01 10:49:18 +01:00

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

Philipp Oeser commented

2021-02-01 10:49:18 +01:00

Can confirm the behavior in a 2.90 [it was not strictly a bug since sometimes the color is meant to be used as an alpha].

This changed though in 0696eaa3e8, so now the images Alpha socket should be used (instead of the Color).
And was improved further in ae82410329

Please try a fresh build from https://builder.blender.org/download/ and report back if the issue persists for you even in those fresh builds.

Can confirm the behavior in a 2.90 [it was not strictly a bug since sometimes the color is meant to be used as an alpha]. This changed though in 0696eaa3e8, so now the images `Alpha` socket should be used (instead of the `Color`). And was improved further in ae82410329 Please try a fresh build from https://builder.blender.org/download/ and report back if the issue persists for you even in those fresh builds.

Ralf Schwarz commented

2021-02-01 16:38:48 +01:00

i did not expect the change in the node shader wrapper ... I checked io_scene_fbx for a code change, so no wonder, I searched at wrong place. ;)

The tweak is good and will help, saving and loading blender files as fbx is "more correct" now.
I know that there will be always a difference between fbx and blender materials ... I struggle with unreal engine here and there.

But yes all okay in e.g. the 2.92 beta.

Thank you for your help. Ticket can be closed

i did not expect the change in the node shader wrapper ... I checked io_scene_fbx for a code change, so no wonder, I searched at wrong place. ;) The tweak is good and will help, saving and loading blender files as fbx is "more correct" now. I know that there will be always a difference between fbx and blender materials ... I struggle with unreal engine here and there. But yes all okay in e.g. the 2.92 beta. Thank you for your help. Ticket can be closed

Philipp Oeser commented

2021-02-01 16:45:34 +01:00

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

Philipp Oeser closed this issue

2021-02-01 16:45:34 +01:00

Philipp Oeser self-assigned this 2021-02-01 16:45:34 +01:00

Philipp Oeser commented

2021-02-01 16:45:34 +01:00

Thx getting back, will close then.

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FBX Importer, transparency of principled is connected to incorrect color (not alpha) output #85234