obviously, the round endmill cannot reach all the way into the corners, so some material is left and all corners end up rounded to the diameter of the endmill. One way to mitigate this is to use a smaller endmill, but cutting a large pocket using a very small endmill would take forever, so a better alternative is first cut the pocket normally with a large endmill, then run a second toolpath will a smaller endmill, that will only work locally in the corners. In advanced CAM tools, this is easy using the "rest machining" option described later below, where the CAM is smart enough to figure out how much material is left and where and to produce a second toolpath with a smaller tool that will only cut there. At the time of writing Carbide Create does not support rest machining, but you could fake it by manually creating additional geometry. In the example below, a 4.5×4.5mm square was added in one corner, with an associated pocket toolpath using a 1/16'' endmill. The corner will still not be perfectly square, but its radius will be 4 times smaller, so it will look much closer to square.