Guide curves, guide curves, and more guide curves. Essentially, unless you have very simple geometry, or don't care about the accuracy of the feature, you will probably need a guide curve for each critical vertex of your profile.
One technique I find helpful for generating the guide curves, and later checking the accuracy of the sweep, is to draw in the profile at every inflection point along the path. It can get tedious for complex shapes, but it saves time when debugging later.
Barrel cams are hard to do in SW. Sweeps don't work and lofts always twist. I did find some success making a barrel cam with a rectangular track for a cam follower by making a cylinderical surface with the cam cut in it and then thicken it to the depth of the track. Surfaces always thicken perpendicular to the surface, so I got walls that were perpendicular to the surface and a fixed distance apart. It looks right, but I never analyzed it because all I needed was a good picture. If you give me your email address I will send you the file.
There are several methods to do these:
1.) Sweep or Loft (use guide curves), as you mentioned work, but you need to be very careful. They can be tricky, but once you figure out some of the do's and dont's very effective. When determining if you should use a sweep or a loft, there is one simple rule:
If the profile is always the same shape in which only dimensions vary, use a Sweep. For example, the profile is always a triangle, with 3 sides.
If the profile changes shape other than simple dimensional variations, use a Loft. For example, the profile changes from a circle to a square.
2.) Sheetmetal functionality can also be used. Create a sheetmetal cylinder (359.9deg), unfold it, cut the cam profile, and then refold it. Then add any other necessary solid features like filling the center of the cylinder etc.
3.) The new wrap functionality in SWX2004 could also be used to wrap the cam profile onto your cylinder.
