Using heightmap with Grblcontrol or Candle

In this video I&show in detail how to use the heightmap feature of grblcontrol to make pcbs on a Banggood 3018 cnc router. With a heightmap you can compensate for height differences, or wobbling of the pcb. The V-bit is used as a probe to measure. The router slowly dips the bit until it makes electrical contact on numerous points of the pcb, thereby creating a &map&of the pcb. Candle is the new name for Grblcontrol, but it&essentially the same