to create bald spots I drop the guide length to zero. This has two immediate problems - you can't see them anymore and the direction is non-existent which leads to wacky interpolation from surrounding guides.
To get around this I add a length mod and add a map. It would be nice to use the brush and paint it directly on the mesh.
The guide channel documentation doesn't make much sense to me - can someone shed some mor elight on this process.
