How to import the FBX model with mateiral

Dear developers:

I am new to Optix and have gone through the Documentation and quickstart guide already.
I use fbxsdk to import the model, but the material display is incorrect. Could you tell how to import material?

Please keep working through the OptiX Programming Guide and examples. What you need to learn is the following:

The Material node in OptiX holds a closest hit and any hit program which you need to implement to handle a material system as needed. Means, first you need to know how an FBX material is working exactly and can then implement the necessary closest hit and any hit programs in an OptiX renderer.

If you have experience with shaders in a rasterizer API, the OptiX closest hit program basically contains the calculations normally done in a fragment shader.

How these programs look like also depends on the underlying renderer implementation itself and that is completely under your control and responsibility.
You would need to implement code to calculate the radiance on a surface hit point (evaluation of the material and lighting) and some code which calculates the direction of the next ray(s) (sampling of the material).

If you search the OptiX example source code for “closest_hit” you’ll find some simple example implementations. Either for Whitted rendering as used in the optixWhitted example or in the optixMeshViewer which handles the OBJ MTL material model a little (look for “phongShade”), or for a simple Lambert shading model for global illumination inside the optixPathTracer.