How to change a SPLINE to a regular curve....?

Ronald,

I saw your original post a few days ago and was meaning to reply, but, work etc.

By regular curve I presume you mean a segment of a circle, easily defined and translated from one format to another.  You are not going to get "the exact arc" you already have, but you should be able to get close enough (within manufacturing tolerances).

As I've said before in other posts here, there are programs out there that are supposed to be able to convert a spline or polyline into tangent arcs, but I have not seen or used any of them.  SolidWorks does not have "one click" conversion process that I know of.

The only way I have ever successfully converted a spline into tangent arcs (I used to do it a lot for laser cut parts) is to manually trace over the spline with a combination of arcs and lines as required.  You can eyeball "close enough" to get the look you need and/or measure how far off the spline you are getting if the deviation is critical.  This is one of the few situations where I would use the "Fix" relation to help fully define the sketch.

I have most done this to convert hand sketched "art" (using the Sketch Picture... tool) into laser/water jet cuttable parts.  But occasionally to translate a design where the designer calls for an ellipse but the laser operator wants arcs. In which case I put the required ellipse in as construction geometry and then trace over it with arcs. This sounds like what you will probably want to do.  If your spline is complicated, save early and often as you go along.

Ron,

I'm on 2015 but I can assure you that the "Composite Curve" Scott mentions has been around a lot longer than 2013. I'm not sure it's what you want for this problem, but have a look at least, it's good to know about the various tools available.  As you say there are more and more features and some older, but still quite useful, ones seem to get lost in the crowd.