Compatibility of exporting FBX with multiple color attributes to other software #104827

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Andrej · 2023-02-16T16:52:34+01:00

Andrej commented

2023-02-16 16:52:34 +01:00

Blender Version: 3.4

If you have multiple color attributes and export object to fbx and then open in 3ds MAX, Substance Painter (there is probably more software with that problem, just the 2 programs I know about atm) they treat first color attribute as the main one and discard every other (Substance Painter) or just put them to some other map channels (3ds Max). Some other software could have similar problem with UVmap. Basically it creates some minor software compatibility issue.

So the order of color attributes is important but in Blender there is no option to easily prioritize some color at export. There is actually no option easily move colors in the list

Ideas how to solve that problem:

Add in Blender FBX exporter option to "prioritize active color attribute" - basically it will export obj.data.color_attributes.active_color as the first one to make sure other software will see it. That's easy to implement - if everyone agrees I can create pull request with that feature.
Add buttons to change order of attributes in the list to keep the main one on top.

Blender Version: 3.4 If you have multiple color attributes and export object to fbx and then open in 3ds MAX, Substance Painter (there is probably more software with that problem, just the 2 programs I know about atm) they treat first color attribute as the main one and discard every other (Substance Painter) or just put them to some other map channels (3ds Max). Some other software could have similar problem with UVmap. Basically it creates some minor software compatibility issue. ![image](/attachments/006f4f3b-2601-4b49-bfcc-9fa9543e09a2) So the order of color attributes is important but in Blender there is no option to easily prioritize some color at export. There is actually no option easily move colors in the list Ideas how to solve that problem: 1) Add in Blender FBX exporter option to "prioritize active color attribute" - basically it will export `obj.data.color_attributes.active_color` as the first one to make sure other software will see it. That's easy to implement - if everyone agrees I can create pull request with that feature. 2) Add buttons to change order of attributes in the list to keep the main one on top. ![image](/attachments/c40ffeb5-478b-4d20-a59e-1eb5f4376a74)

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Andrej added the

labels 2023-02-16 16:52:35 +01:00

Scurest commented

2023-02-16 20:48:40 +01:00

Add in Blender FBX exporter option to "prioritize active color attribute" - basically it will export obj.data.color_attributes.active_color

Requested (without the option) at blender/blender-addons#104214. OBJ and glTF also do this. The glTF exporter used to use the first but switched for the same reason: you can't control the order anymore.

There's still one problem though: do you use the active attribute (the one that's highlighted) or the active render one (the one with the clicked camera)?

Currently OBJ uses the active one, but glTF uses the active render one. It'd be great for the exporters to all agree.

> Add in Blender FBX exporter option to "prioritize active color attribute" - basically it will export `obj.data.color_attributes.active_color` Requested (without the option) at https://projects.blender.org/blender/blender-addons/issues/104214. OBJ and glTF also do this. The glTF exporter used to use the first but switched for the same reason: you can't control the order anymore. There's still one problem though: do you use the _active_ attribute (the one that's highlighted) or the _active render_ one (the one with the clicked camera)? ![Color attributes showing difference between active and active render](/attachments/ac73054c-65d9-48c8-bb17-d3808c4a8e37) Currently OBJ uses the active one, but glTF uses the active render one. It'd be great for the exporters to all agree.

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Andrej commented

2023-02-17 10:05:17 +01:00

There's still one problem though: do you use the active attribute (the one that's highlighted) or the active render one (the one with the clicked camera)?

As far as I know "active render color/uvmap" will be used if those nodes in shader graph will be left without specifying attribute.

And "active color" is used by this thing

Weirdly enough, on contrary to colors "Active Render" for UVMap also defines what UVMap that will be used in viewport (which is probably another subject).

From coding point of view I met obj.data.color_attributes.active and obj.data.uv_layers.active all the time and really rarely I see checking [a for a in obj.data.uv_layers if a.active_render][0] (which is kind of weird because active_render is the uvmap that you'll actually see everywhere).
For color attributes I've no idea where render flag is even stored.

If we look at some other render properties export handled - when applying modifiers during export the viewport settings is used, not the render ones.
From that perspective currently using active_color seems to be better way to prioritize colors and active_render to prioritize UVMaps.

> There's still one problem though: do you use the active attribute (the one that's highlighted) or the active render one (the one with the clicked camera)? As far as I know "active render color/uvmap" will be used if those nodes in shader graph will be left without specifying attribute. ![image](/attachments/a9969f23-06e5-4a4c-97aa-1630577b806d) And "active color" is used by this thing ![image](/attachments/596188b3-85f0-41de-aa27-28e8521b52f0) Weirdly enough, on contrary to colors "Active Render" for UVMap also defines what UVMap that will be used in viewport (which is probably another subject). From coding point of view I met `obj.data.color_attributes.active` and `obj.data.uv_layers.active` all the time and really rarely I see checking `[a for a in obj.data.uv_layers if a.active_render][0]` (which is kind of weird because `active_render` is the uvmap that you'll actually see everywhere). For color attributes I've no idea where render flag is even stored. If we look at some other render properties export handled - when applying modifiers during export the viewport settings is used, not the render ones. From that perspective currently using `active_color` seems to be better way to prioritize colors and `active_render` to prioritize UVMaps.

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Andrej referenced this issue from a commit

2023-02-25 13:04:28 +01:00

Option to prioritize active color at export

Andrej referenced this issue from blender/blender-addons

2023-02-25 13:07:41 +01:00

Option to prioritize active color at export #104435

Bastien Montagne referenced this issue from a commit

2023-03-06 16:22:04 +01:00