Dear all, I tried to generate section curves on a surface from a series of section planes. There are always ghost section curves -- with NO reference to any section planes. This is what I have done:
1. Make a surface and a curve in Rhino and link them to Grasshopper. 2. Generate a series of perpendicular frames (planes) on the curve by Perp Frames tool. 3. Use the frames as section planes to yield section curves on the surface by BRep | Plane section tool. Normally 8 section planes yield 8 section curves, if I understand it correctly. But it ended up 10 section curves in which 2 ghost curves came out of nowhere close to the ends of the spinal curve -- as the screenshot shows. <a href="http://picasaweb.google.com/lh/photo/0yQEJgdJd-DjXSJrmVFVcA? feat=embedwebsite"><img src="http://lh4.ggpht.com/_9ndfA_Jn3Cs/ Seazp1Wa5PI/AAAAAAAAAWc/XTNzsTLRcjs/s144/gh-ghost1.jpg" /></a> <a href="http://picasaweb.google.com/lh/photo/0qQhkOLNyvsLdL9Nx-DKyQ? feat=embedwebsite"><img src="http://lh3.ggpht.com/_9ndfA_Jn3Cs/ Seazq8OFt0I/AAAAAAAAAWk/3Pi_CrsOnLk/s400/gh-ghost2.jpg" /></a> Files: http://dl.getdropbox.com/u/716203/grasshopper/ghost_section_curves.3dm http://dl.getdropbox.com/u/716203/grasshopper/ghost_section_curves.ghx I don't know if it is a bug or the mysterious result of intersecting BRep components. Any comments would be appreciated. Junehao
