Cloth.vertices and Cloth.indices

In the documentation it says that the normal indices may not necessarily correspond to the indices of the source mesh. Can you explain what this means? Also, how can I render the simulated mesh each frame from within a render plugin in DirectX if I cannot use the mesh indices. I also need the mesh texture coordinates for mapping a texture on the mesh. How can I make the correspondences?

What they are saying is that the cloth simulation only has one vertex per position because its only used for the simulation. The source mesh may have multiple vertices per position if the normals are split, if there is a UV seam, etc.

In general, to render cloth you should use the InteractiveCloth or the SkinnedCloth components. Those components take a regular mesh, that mesh can have materials, and you can write custom shaders for those materials. It’s hard to say more without knowing the actual effect you are trying to achieve beyond “render plugin”.