DingoOz,
Remember that the sheet metal tools are intended for bending flat metal with simple curvature, that is a linear bend, or curvature along only one direction. Complex contour where the metal is curved in two directions can never be flattened without deforming the metal and is beyond the capabilites of the sheet metal tools. As an example take a couple pieces of paper and tape them together as a traffic cone shape and try and then take scissors and cut the part to become a flat pattern. You can either cut the base off, or almost completely off leaving only a tab and slit the cone up the side or you can use CBL's trick of making radial cuts toward the cone. He gave his cone flattened sides because a true cone would require many small strips, i.e. approching infinity. By the way the first method I mentioned where you leave the base connected to the cone by a tab would not work because the material for the cone would lay on top of the material for the flange which means it could not be made from a single piece of material.
I always like to think about a flat pattern in paper. Can I really cut it so it lays flat? Think about the cuts that would be needed for a sphere to lay flat. Something like the world maps with curved triangular tabs running toward the poles, only since we are working with software that requires mathematical precision the number of curved triangular tabs would be many. This is positive complex curvature. Negative complex curature would look something like a saddle and zero complex curvature is what is really simple curvature which only bends in one direction and can be flattend without deforming the material.
-Kirby
-Kirby
Kirby Wilkerson
Remember, first define the problem, then solve it.
