I cleaned up the cube brush tip code quite a bit; more remains to be done. There is a new function to initialize cube tip matrices, SCULPT_cube_tip_init. It's currently only used by the paint brush, I'll need to do a bit of testing before using it for clay strips and multiplane scrape. Note: SCULPT_cube_tip_init uses the brush local matrix code to avoid code duplication (and to take advantage of the debouncing that is done there).