I'm trying to create a shape that tapers along it's length, has a variable pitch and the profile changes from Ø2.8125 at one end to Ø3 at the other end. I believe I know how to do it but SolidWorks won't cooperate. I'm using sweep with a variable helix as the path and a second variable helix as the guide to enlarge the profile as it progresses down the helix. I believe the problem is because of self intersecting geometry but I can't find a work around. Sometimes it gives me a preview that looks good and sometimes it just creates a little fraction of the part, (see picture). Can anyone get this to work?