Please try the following:
1. Create a curve with a bevel a surface
2. Create another one
3. Assign different materials to each of them
4. Import in Octane
I find that Octane shows the different materials in the node mesh but just one of them is assigned to both the curved surfaces.
If I trasform the curve/bevel to meshes everything's ok. The problem is that I'm animating the bevels so I cannot mesh !
Any workaround ?