Hi all and especially those who know about FBX SDK...

I've been using fbx sdk for some time now but I couldn't put the finger on how to know if a material or a piece of geometry is supposed to be double sided.

I can't find a flag or something that could tell me, this geometry needs to be rendered with no culling. I know in Maya this information exist but how is it exported to fbx file. I checked the forum in autodesk sdk but couldn't find any good answer. I know the community here has some serious fbx developper so I hope to get some hint.

I am currently working on a model which has a cape, it looks good in Maya obviously but the exported file doens't even show properly in fbx review. I know this is not really surprising... When loading the exported file (fbx) in Maya, I can see in the cape in the section "Render Stats", Double Sided is ticked. So somewhere this information must be stored.

Does anyone has an idea on how or where this information is stored in the sdk?

Many thanks.

I have the same I issue, all I found about it is that 3ds Max and Maya do not export such info to FBX, I do not know if it is still true, this is issue is on halt for me, there could be some dirty workarounds like adding custom properties to the materials or the meshes.
 

I'm happy to see I'm not the only one in this situation and that the answer is not so trivial.

Also I don't believe this information is coming from the custom properties, it could be a workaround for sure but I need to determine this from any FBX file.

Thanks for your post, let's hope we'll gather more informations here ;o)

Culling is determined by vertex order for a polygon within the fbx file.  Either clockwise, or counterclockwise. That's why this information isn't stored explicitly as a flag.  Thus, sidedness is enabled/disabled within the shader, not the model file.

https://learnopengl.com/Advanced-OpenGL/Face-culling

Thank you goalied00d for your answer but I know about culling and that is precisely the problem. In the Fbx file, the geometry has some winding order determined by the indices. And there is only one triplet of indices per triangle. So how do I know this triangle should be rendered both sided?

So to use the proper shader, I was expecting to find some informations in the materials.

Thank you anyway, might help others.