I had a guy ask me for a cone unroller back in December. I made him the attached autocad lisp. There are a few functions in Vlisp that make some of this type of thing a bit easier. It doesn't use anything in AutoCAD (pcg ect), it just reads and writes a pts. Type appload, find the lsp file and then press load,ok, then type in Uncone. You need to have a the geometry of a pointed cone so you might need to do a little bit of math if you have a sliced cone (truncated) to figure out the height, and give the program the bottom radius, the height of the cone and the centerpoint at the bottom. You need to give it data of a cone with the point upwards, as a unified pts file.
It will unroll it as if you turned the cone with the point pointed south and unroll it clockwise from north, with 0,0,0 being the point of the cone. Obviously it hasn't been significantly beta tested, so have a go with you data and have a good look at the results. I tested it with 28 points and it seem to be doing everything ok.
I am pretty sure this is what you wanted to do. Hopefully it will be of some assistance.
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