Color Not Showing on Some Geometry

[vincent-edward-lo]

Hello,

I am using Maya 2018 and exported out a glTF file with a character. For the materials, I am using the glTF_PBR.ogsfx shader. Most of the materials simply have a color and normal map plugged in.

However, when I bring in the glTF into several different viewers, they all show the same thing.

Here is a screenshot from Maya.

As you can see, I have some primitive spheres and planes showing the same materials as the materials on the character. The spheres appear to be rendering properly, but not the character.

For another test, I applied a single material to the entire character and just changed the Base Color Factor. No maps were used. I still got a similar issue...

In addition, when the mesh is animated, some faces appear to be flat shaded? I'm not sure if this issue is related.

The normal maps appear to be showing properly, but why are some pieces of geometry not showing color?

[ziriax]

Are you using the downloadable released version, or did you build from the develop branch source?

Can you paste the log from the output window and history window, maybe some errors or warnings appear. For example, tangent vectors could be broken.

[vincent-edward-lo]

Hi thanks for the response.

I'm using the downloadable released version. I downloaded the .zip from this page
https://github.com/WonderMediaProductions/Maya2glTF/releases
and executed the deploy.bat file.

Here's the log from Maya's Script Editor.

Is there another output window I should be aware of?

[ziriax]

Sorry, I missed your reply.

Yes, it's really the output of the native Maya output window, it looks like:

If you have Maya 2019 installed, you could try the upcoming 1.0 release:
https://github.com/WonderMediaProductions/Maya2glTF/files/4103175/maya2gltf_1.0_a6a059d_maya_2019.zip

[vincent-edward-lo]

Thanks, here is the Output log for Maya 2018. I used the glTF_PBR.ogsfx shader, changed the "Base color factor" to blue, and applied it to every object, so no texture maps were used.

outputLog_blue_farah_static.txt

The resulting glTF export looks like this:

All the objects should be blue, not just her eyes.

I'll try out the 2019 version, thank you for providing that.

[ziriax]

Very strange. Can you also try exporting with the -mts flag?

If you can send me your scene (or just a single polygon from your mesh that has the problem), I will take a look at this.

[vincent-edward-lo]

Okay, so a few things:

1. I tried the 2019 version of the exporter. For some reason the shader properties were not showing up for me.

2. Went back to 2018 and tried using the -mts flag. It successfully exported, BUT it still showed the same weird results.

3. In 2018, I exported out an OBJ with the following settings.
   

And just to double check, I brought that OBJ back into Maya, applied the same blue material, re-exported as a glTF, and it shows up blue as it should in a glTF viewer!

4. I then re-exported out as an FBX with the following settings.
   

I brought this FBX back into Maya, applied the blue material, re-exported as a glTF, and it shows up incorrectly. Still gray.

I've attached the FBX here.

shirt_Binary_2018.zip

I guess I've always had the hunch that something is just wrong with my geometry, I'm just not sure what exactly or how it happened.

EDIT: So I did another quick test, and I found out the the problem exists on geometry sent to Maya using Zbrush's GoZ button. I'm pretty sure I used that GoZ button to bring geo over. Something in the transfer breaks the geo,,?

[vincent-edward-lo]

If I export out the geometry from Zbrush manually as OBJs (without using GoZ) and re-assign the same materials, I can see the texture maps properly.

I guess this can be a workaround for future models coming from Zbrush to glTF, in case the issue becomes too difficult to find.

[ziriax]

Thanks for sharing your model.

Something is really broken with this model, because I import your model, open the UV Set editor, and then clickon the map1 set in Maya, I get the error:

Error: file: C:/Program Files/Autodesk/Maya2018/scripts/others/texturePanel.mel line 1001: No object matches name: Shirt_RENShape.uvSet //

I'm not a Maya expert myself, but it seems somehow the uvSet relationship is broken...

If you pass the following flags: -mpa POSITION|NORMAL|TANGENT to the exporter, it will export without UVs, and then the GLTF will work, but that's not what you want of course.

I think first the error needs to be solved in Maya...

[vincent-edward-lo]

Ah ok. Thank you so much for looking into this!

[ziriax]

Nevertheless, I will look into this as soon as I find some time. Indeed, exporting and reimporting as OBJ fixes the problem.

I noticed that when importing the corrupt GLTF, I get validation warnings that the texture coordinates are not used. I'm curious what is going wrong here...