The next step for me on my virtual sculpting path is to have a CNC robot carve one of my 3D ZBrush compositions. My friend and colleague, Carl Nelson invited me to send him one of my virtual sculptures to try on his 3 axis CNC machine. CNC stands for Computer Numeric Controlled machine.
Carl brought a Pro4824 CNC router to the NWSSA Oregon International Stone Carving Symposium at Suttle Lake, USA (above) in August that had been adapted for carving stone. I emailed him my virtual ZBrush file in advance, and Carl was able to partly carve my abstract female torso in Texas limestone. Since there was enough space available in the chosen limestone block, Carl added a second torso to the file and carved two identical sculptures, inverted beside each other.
Since this CNC machine has 3 axis, it was only able to router down to the widest points of the sculptures, but unable to undercut from the top. After getting to the halfway point, Carl then flipped the stone over so the machine could successfully carve the other side of the sculptures.
The ZBrush file (above left) is a mesh and is not sufficient computer language to operate the CNC machine, so Carl had to use a translator program to enable the machine to carve the shape I designed. Above right is an illustration showing my abstract female torso laying on her back in black, translated into a language the CNC machine can understand. The machine needs a 0-0-0 reference point in order to carve the sculpture correctly. Therefore, Carl imbedded the bottom of the design in a block that would not be carved by the machine. Since the top of the sculpture is quite delicate, Carl left a block of stone at the top as well. The yellow lines show the path of the rotary carving head of the CNC machine.
The raw limestone block was secured into the carving bed of the CNC machine, and after a few hours, the machine worked away, removing the superfluous limestone and leaving the image of the two torsos. The sculptures are revealed looking like a topographical map, as each successive pass of the carving head was approximately 1/32″ down from its predecessor.
Once complete, I took the sculptures back to my studio to separate them into two pieces. I will complete one of the sculptures, but leave the other as is for future demonstrations. Here is a short vid of this part of the process:
What do you think of me using a mechanical assistant to help me to carve? Would you feel differently if I employed a human as an assistant? Let me know in the comments section below.