Border alignment artifact

When rotating a cube, the cube representing the rotated particle will have some areas where there is no information.

See the effect here.

 u1=dynamo_rot(rand(64,64,64),[45,45,45]);
 u2=dpkgeom.rotation.sharpRot(rand(64,64,64),[45,45,45]);

  figure;
  subplot(1,2,1);dslices(u1);subplot(1,2,2);dslices(u2);