I don't know if you can consider it blazingly fast, but Blender has ray intersections from Python, and IIRC it was fast enough to make a 256x256x256 voxel grid

I don't know if you can consider it blazingly fast, but Blender has ray intersections from Python, and IIRC it was fast enough to make a 256x256x256 voxel grid in a couple of seconds with raycasts.