A. Introductory remark The functions "contour correction", "follow contour", "thin out contour" and "pocketmilling" are special functions, which you find in the ICON groups CAM and Edit. They are extremely complex mathematics and need a lot of development. From version nccad4.5 onwards, the above described functions are integrated in a way, you usually find only in professional CAM-programs of the 5.000-Euro-range. However, we admit that there are some gaps to be filled and further development is needed. You can use them successfully if you understand the principles.
B. Concerning contour correction If a contour has a slit, the mill must not be broader than the slit, more exactly: the diameter of the mill must be at least 0.2mm smaller than the width of the slit; otherwise, the corrected contour will not be generated. Normally the contour is done very well, if the contour consists of a series of lines resp. of a polygon. There can be combinations of arcs where no clear mathematical solution is possible, the error message will appear "contour correction not possible". With succeeding arcs it may be helpful to generate succeeding lines (instead of arcs) by "thin out contour" and to apply contour correction then.
C. Thinning out to succeeding arcs If you intend to use contour correction and thinning out of a contour with a contour of lines or polygons, you should always make the contour correction first before thinning it out to a series of arcs.
D. Pockets We repeat again: This function cannot always guarantee a solution. Sometimes it may happen that "parallel to contour" does not give a good result, but "parallel toangle"does. It is necessary for you to make your own experiments at the beginning. A different diameter of the mill, for example, can often help to make it work better.