This seems like a pretty popular route that could be of use. This is a repost from Solidsmack.
Illustrator to SolidWorks Quick Tips
Ha! you’re joking right? Nope. To bring an Adobe Illustrator File into SolidWorks, you need to have Illustrator CS3 or newer installed. You can get a Trial version here. Yeah for you.
Paths only or DIE
Not die for real, but die from picking and deleting line you wish were not there. Make sure the .AI file you import only contains the paths (line art) you need and you’ll be much happier. What if it contains fills, shading, and a bunch of other mess?
Pick your Paths
… and your friends, but not your friends paths, or their nose. For graphics with fills or an over abundance of lines, in SolidWorks zoom in on the paths (splines) you need. Right-click and hit Select Chain to select only the splines you need, then copy and paste them into a new sketch. Delete the other sketch after you’re done.
Kill the Excess
After import, thin lines in the sketch may mean there are lines on top of each other. If you plan on using the imported paths, you’ll want to clean up the lines. Really, if it’s a large piece of artwork, it’s going to be easier to snort your nasal spray and…
Trace the Paths
You’re rocking along now, but those imported paths are way too complex. Start a new sketch and use the imported paths to create simple lines, arcs or splines in SolidWorks. Not ideal, but can really save some load time and the time of getting the imported lines cleaned up.
Illustrator Paths For SolidWorks Surfaces?
I’ve had a bit of luck using paths from Illustrator to produce smooth Curvature Continuous surfaces. It’s a little hit and miss and while you may be limited to an import from Illustrator, you’ll have more capabilities after you bring those paths into SolidWorks. Amazing as it may sound, the Spline (Path) tools in SolidWorks are much easier to manipulate.
I’m so not the surfacing wiz in SolidWorks though, so if anyone has used Illustrator to aid in the creation of surface models, throw down some tipage in the comments, and I’ll have a wild sea otter visit you with some bonus points. That’s a lie, I’ve never met a sea otter I liked.