A method is provided for rendering 3D voxel data including plural voxel sets, while eliminating artifacts that may result from the plural voxel sets colliding with each other ("voxel interpenetration"). In one aspect, the method involves an extension of the splatting approach, and uses a z-buffer associated with each pixel to indicate the z-depth of a voxel to be painted onto the pixel. According to the method, first, the z-buffer for each pixel is reset (cleared). Next, for each of the plural voxel sets, one voxel set at a time (sequentially), voxels within the voxel set are traversed until an occupied voxel is found. If a z value of the occupied voxel is less than a z value stored in the z-buffer, the z value of the occupied voxel is stored in the z-buffer and the occupied voxel is painted onto an associated pixel. Then, the next occupied voxel is considered.