An execution plan segment of an execution plan can be received at a control unit of a computer numerically controlled machine from a general purpose computer. The execution plan segment can define operations for causing movement of a moveable head of the computer numerically controlled machine to deliver electromagnetic energy to effect a change in a material within an interior space of the computer numerically controlled machine. The execution plan segment can include a predefined safe pausing point from which the execution plan can be restarted while minimizing a difference in appearance of a finished work-product relative to if a pause and restart are not necessary. Operations of the computer numerically controlled machine can be commenced only after determining that the execution plan segment has been received up to and including the predefined safe pausing point by the computer numerically controlled machine.
