Its the type were the printer prints 1 material and the operator manually adds the others. I've done this to put captive nuts into a 3d print by adding a M00/M

Its the type were the printer prints 1 material and the operator manually adds the others. I've done this to put captive nuts into a 3d print by adding a M00/M01 into the GCode right before the layer they were covered up in.