Not so planer swept face?

Did you use a guide line to maintain alignment? Horizontal and vertical relations don't always hold well in a sweep.

The obvious question is if this is really a planar surface and you want to use it as a planar surface, why are you using a sweep to create it? Why not use a Planar Surface feature? Sweeps by their very nature are interpolations, so there's a bit of filling-in-the-gaps going on, which could easily explain what you are seeing.

Re-reading, I'm going to guess that you're making a solid instead of a surface, where the top of the solid has some shape and the back of it is supposed to be flat. You could just make a big planar surface and do a "replace face" to replace the existing solid face with the truly planar surface. Don't do a cut, because material might need to be added as well as removed, which is what a replace face will do.

Anyway, there are several ways you can create a truly planar face, but lofting and sweeping would be on the bottom of my list of most reliable techniques for that.

Good luck,

Matt

If it truly was an elliptical path, then there isn't any planar surface. The surface is curved perpendicular to its path everywhere along the path. If you sweep a straight line along a straight line, then you will get a planar surface and you can put a sketch on it.

Jerry Steiger Tripod Data Systems "take the garbage out, dear"

Can you post the file to the SolidWorks forum at