Octree

Is there an octree package for Common Lisp? I.e. something that would allow setting voxel on/off and then do A-star on resulting big cubes.

Here is my nearest-neighbour discovery algorithm:
 1. push random sub-quad inside this quad onto processing stack
 2. pop top quad and for each it's edge's segment push quad, containing this segment, onto processing stack
 3. if stack isnt empty, goto 2.

Note: hash poped quads by their XYZ

it should be faster than just poping every voxel.