Which brep contains a vertice/curve (not which vertices/curves are inside a breb)

Hello community

Perhaps someone knows the solution to this.

Context:

I want to be able to quickly and reliably simplify a model. The solution I want to pursue is making an octree representation of the model (I got the idea from Radiance).

I want to progressively divide a cube into smaller cubes whilst only retaining the cubes which intersect with the model I'm copying. In effect, I'm carving away at a monolithic block to a shape that represents the original to a level of detail specific to what I want. I like the idea of ending with cubes as they will always behave the same when I come to further process.

Problem:

How do I scan the cubes to differentiate which are intersected by the original model (or have vertices of the original inside) and which are not. Its easy to define which curves or vertices are inside one of the cube (there are standard functions for this) but this does not differentiate the cube. I cannot think how to do it on a cube by cube basis.

I've gotten as far as above by considering the distance of the centre of the cube to the nearest vertice of the original model. This is not quite accurate and VERY inefficient.

Anyone got an idea?