You're fortunate to have access to CATIA. I looked at info regarding it online this morning. I also recall it was available in the 90s when I started with Cadkey, now KeyCreator. Looking at the project galley files I didn't see anything indicating it had more surface capability than KC. Those files are usually a good indicator of the complexity a program can produce. I suspect most programs use similar surface and solid modelling geometry. Most do well with solids and surfaces developed around geometric primitives, but the surfaces where there is the ridge in the attached photos, may be a little too contorted, even though they are blending larger surfaces generated from arcs.

I've looked at Rhino, particularly the jewelry designed on it. That seems to have the capability of more complex surface work. I teach at a small engineering college and Rhino was available for a year or so. It seemed easy enough to learn, but as I have done everything so far that I want with KC, I didn't make much of an effort to learn it.

Here are the 2 photo links of the double guide with the anomaly, the ridge between the two openings. It's all of .01" and easily/quickly sanded down to fair the surface of the sign maker's foam. I suspect most surface software would produce a similar ridge, given the blend between large easy radii, and the tight area between the openings. Were I to look, there's probably an easy way to correct it in KC.

Good luck with your double guide, I wish more people would try these. In my experience, they make a positive difference.