Since the height of materials can vary, we will create toolpaths reference to the bottom of the stock or the cutting bed. This avoids cutting deep into the flat cutting surface, thereby prolonging its useful life, and cuts all the way through the material. For highly accurate engraving or non-through cuts, tool paths can be created that reference the top of the material.
Since no machine or surface is perfectly flat, we add a - negative vertical offset to profile cutting toolpaths. It is a small offset of .01 inches but it helps cut all the way through the material while minimizing damage to the table surface.