3-D is using a multi-axis machine. With regular machining you only had to fix the part to the bed which could move up, down, left, right, and sometimes tilt. Or the part stayed still and the tool moved in the same manner.
Multi-axis machines the part gets to move around the tool, so you can pull off the same things you did before, just more efficiently and you get to call it really cool names.
Multi-axis machines the part gets to move around the tool, so you can pull off the same things you did before, just more efficiently and you get to call it really cool names.