I'm trying to slice my .obj file into .svg files. The .obj file is hollow, but the .svg slices I get by running skeinforge are filled in. For example, if I was trying to print a basketball, it is giving me a .svg file that is a filled in circle, rather a hollow circle. I was wondering if this is a setting issue or maybe something is wrong with my .obj file. Any insight would be a great help, thanks.