Axis -- depending on type of cnc machining should have from about one to six axis that also determine the as well as what it is supposed to experience.
There are several people to do this editing line by line because elements, including colors is simple and easy. Now think of an intricate shape the actual scaling it up or down would consist of. This would include massive changes to it and reviewing it line by sequence. We are talking thousands of lines here vs. moving back and quickly scaling the model and spitting out innovative G-Code.
Blind hole floors. These kind of are always a problem to do; either you mill them extra deep before heat treat and grind to fit, anyone leave stock for post heat treatment machining. Either way, always be a bother to get the depths directly in a timely manner. While jig grinder, you leave them shallow before heat treat, and use a CBN wheel to almost instantly grind the depth actually. This is more rapidly and easier than hard milling or guessing at the depths when grinding.
One thing people don't appear to understand is that all these pieces in order to fit together like a puzzle, merely the gaps are not to be more than about one-eighth of a hair (.0005 in.). Its so difficult, until the shapes take presctiption angles or have weird radii which can be very complicated to produce and figure out.
Most of this time we never even give an extra thought as to how exactly where there is these things come since. Only when they to be able to properly work do we give them notice.
The material to be shaped is taped in order to a block with double sided recorded argument. This must be done carefully so that it does not come from all the block during machining.