Exports look weird

[solodeveloping]

Describe the bug

I had a problem with a model with clothes, so I tried to do a naked male export, to go step by step.

And the export is weird., see the screenshots section.

My GLTF export settings:

And the FBX:

Checklist

• If you are using blender 4, did you use the blender 4 specific build?
• If you recently upgraded mpfb2, did you read http://static.makehumancommunity.org/mpfb/faq/ensure_correct_version.html

I'm assuming this is correct

Screenshots / logs

For the Blender model, I did the "bake shapekeys" + "delete helpers" steps:

The GLB:

The FBX:

I also tried export copy in both FBX and GLB, in a new blender file, with "selected objects" checked, and all the recommended settings

Platform and versions

OS: Windows

Versions: See screenshot of the versions, above.

[joepal1976]

Thanks.

The FBX thing merely looks as if it is missing the textures. In the FBX export dialog, there are some settings for texture paths and embedding ("path mode" and the box button beside it for whether to embed the textures or not). Maybe tweaking these might change the situation.

For the glb thing, it seems the shader has gotten confused. When doing a roundtrip with blender-glb-blender, it has not preserved the node setup. With gameengine material:

before export:

after import:

By removing the alpha channel connection, the model shows up correctly in blender.

It seems blender's gltf exporter dislike having the same image texture hooked to both the color and the alpha sockets. I'm not immediately sure what to do about this.

It is obviously a clunky workaround, but maybe there's a way to adjust this on the importer side (godot?). If you can adjust the alpha channel to either remove its dependency on the diffuse texture or relinking it correctly, the character might start looking more sane.

[joepal1976]

@met4citizen : do you have any insight in this behavior for gltf?

[met4citizen]

I haven't seen this exact issue before, but in general, if you need transparency, I recommend using "Mask" mode (Alpha Clip) instead of this "Blend" mode.

As you may know, glTF supports three different alpha modes depending on whether the alpha value is always 1 ("Opaque"), always 0 or 1 ("Mask"), or somewhere between 0 and 1 ("Blend"). Use "Opaque" mode whenever possible. If transparency is required, use "Mask" mode. Only use "Blend" mode when absolutely necessary.

If you want to setup "Mask" mode in Blender 5, go to Shading and add a new Math node before the Principled BSDF Alpha input: Add | Utilities | Math | Math | "Greater Than". Adjust the threshold value until the edges look correct. The node setup should be like this: Image Texture Alpha → Math (Greater Than) → Principled BSDF Alpha.

I no longer have Blender 4 installed, but if I remember correctly, in Blender 4 you need to go to Material Properties | Settings | Set Blend Mode to "Alpha Clip" and then adjust the "Clip Threshold" value.

[solodeveloping]

I just want to point out I just used every default/recommended settings (I think)

There is a blender/godot bridge, maybe I'll try that too

Are we supposed to use Blender 5 (I did not know it was a thing) or Blender 4?

[solodeveloping]

The readme says "Note that MPFB 2.x requires a Blender version of at least 4.2." 🤷‍♂️

[solodeveloping]

Is there a way to configure the export options from a python file? That could be a thing, to help with the godot support

[solodeveloping]

It's weird there are any alpha values no? Since it's just the naked mesh and not the mesh + clothes

[solodeveloping]

As long as there is a texture + uvs, I can make a shader in Godot (I'll try), but it would be nice if it was working by default, I think

[solodeveloping]

I can make a shader + material in Godot, that makes sense

[solodeveloping]

Interesting, the result with the alpha plugged in is not what we see with the default material

[met4citizen]

Are we supposed to use Blender 5 (I did not know it was a thing) or Blender 4?

It should work with both. I'm just another user, and I happen to have Blender 5 installed.

It's weird there are any alpha values no? Since it's just the naked mesh and not the mesh + clothes.

Exactly. Some clothing materials may require transparency, but the base mesh typically does not. Whenever you don't actually need transparency, you should use the "Opaque" glTF material mode by disconnecting the alpha channel before exporting.