I've implemented the volume render using ray-casting in CUDA. Now I need to add other 3D objects (like 3D terrain in my case) in the scene and then make it interact with the volume-render result. For example, when I move the volume-render result overlapping the terrain, I wish to modulate the volume render result such as clipping the overlapping part in the volume render result.
However, the volume render result comes from a ray accumulating color, so it is a 2D picture with no depth. So how to implement the interaction makes me very confuse. Somebody can give me a hint?