Really? It looks like a 32 x 32 grid in the screenshot. That’s 1,024 quads–2,048 triangles. And since it’s all one mesh, the collision traverser will have to test each of those 2,048 trianglse against each CollisionRay.
At the very least, you should subdivide the mesh into several smaller pieces, so the collision traverser can rule out large parts of it based on the bounding volume.
David