Visibility Mapping

I have been doing some modelling using a ray tracer I coded myself, importing stl files. I generate a list of stl object facets visible for a series of coordinates. However, when applied to a large file my code is just inadequate, and I need to map the visible facets for around 2000000 facets for 6000 coordinates. Are there any examples of using Optix for this type of application?

There is a thread with a very similar question already:

This is a more general thread about how to shoot rays from arbitrary points and gather hit results: