DESCRIPTION:

Dilate fromset by size along the given halfaxes.
The newly created voxels (the border) are colored according to
toset. If "onlyto" is given, only voxels from this set are
available for expansion.
The axismask is a bitmask consisting of:
 1 positive X axis
 2 negative X axis
 4 positive Y axis
 8 negative Y axis
16 positive Z axis
32 negative Z axis
The processing steps are separated. This may lead to unexpected
behaviour, if multiple axis are used at once. The filter will
run in the order z,y,x.