In our business, we have knock-out features on our sheet metal parts. The most efficient way to cut the feature uses open single-curve contours as shown in the attachment. The problem is open-contours are not well-liked by any modeling software.

I'm wondering if anybody had any idea's on how-to model these types of features... Trick would be without user interaction. In the end, you want a model that shows the laser-cut slits; however, DXF would only show a single-curve.