Since the implementation of these formats heavily depends on the application you plan to use them in, I can only provide general tips on how this model is supposed to be set up. I will explain how I set the model up in Blender and you’ll have to adapt the specific techniques to your target application.
Download the exchange format you want to use, aswell as the Additional Files which contain all necessary textures from FAB.
Import the downloaded files into your target application and make sure that vertex colors are imported aswell.
The fox’s body has a fairly standard pbr material setup.
You can plug the Color and Normal textures directly into a standard lit shader, or adjust them slightly to match the body’s colors to the fur depending on your target application's render engine.
The AORID map contains an Ambient Occlusion, Roughness andn ID map packed into it’s three channels. You can extract them and use them however suits your target application best.
I use the ID map e.g. to overwrite all of the roughness values, since this gives me more flexibility for lookdev.
The fur is slightly more complicated to set up. The AOLR texture contains an Ambient Occlusion, Normalized Length and Random per Strand map in it’s rgb channels respectively and an Alpha Mask in it’s alpha channel.
To reduce texture memory, I stored the fur’s color in it’s vertex colors.
You could use the Normalized Length and Random per Strand values to adjust the fur’s color with more granularity, but I only use the Ambient Occlusion map to fake a little more depth between the strands.
The NT map contains information to reconstruct the hairs normal and tangent direction. Because of the way the fur atlas is laid out though it should be fine to just use the geometry’s default tangents as an approximation.
Use the following formula to reconstruct the normals: x = NT.r, y = NT.g (1 - NT.g, depending on OpenGL or DirectX), z = 1 - abs((NT.r - 0.5) * 2).
