Are lights in Maya causing shading import issues?

Development Rendering
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1

H-H_2 has degenerate tangent bases which will result in incorrect shading:

I made a hill and house in Maya 2014, exported with FBX. There are no textures in the scene as of yet. When I import, I always get the error posted above. Is this because there are lights in my scene in Maya?

2

There are no lights in my Maya scene…

3

Recompute Tangents is selected:

4

Guess I need the 4.8 Update…

5

Hi,

Degenerate Tangents simply means that you’ve got a UV that is not setup correctly. This could be simple UV stretched face that is causing the issue.

You can read a little more about it here in this post: Degenerate Tangent Bases - Rendering - Epic Developer Community Forums

In 4.7 MikkTSpace tangent basis was added to the engine. Any tangents that do not align with this will kick back the degenerate tangent error. The warning message could use some tweaking to better reflect this as a UV mapping issue though. In 4.8 you’ll still get the same error message with any assets that do not have UV mapping that falls in line with the MikkTSpace method, but you’ll have the option to disable MikkTSpace in the Static Mesh Editors build settings to use the method that was set before 4.7 was released.

I hope this helps.

Tim

6

Thanks for the reply Tim;
UV is textures, isn’t it? I don’t have any textures on the model.

I have a window boolean I can remove and see if the geometry is causing the trouble…

7

The UV is not specifically the texture that is applied, but how the texture is applied.

The UV for the mesh is when all the geometry has been laid out flat in the UV space of 0,1.

This video tutorial covers the basics of UVs and mapping them: The Basics of UV Mapping - YouTube

If you’re using a boolean to cut out parts of your geometry and you’ve not setup a proper UV this would explain the degenerate tangents.

Let me know if you have any other questions. I don’t mind helping where I can. :slight_smile: