Sweeping a spline, Rhino vs SolidWorks



Long-time Rhino user suffering now to learn SolidWorks, hoping someone else here using both can explain the causes for an odd behavior I want to avoid. In sweeping a spline on Rhino things almost always go well. If the spline loops too tightly, I might end up with entirely predictable kinks the same as if a large hose were bent too small, or sometimes the sweep might intersect. In Rhino this is always easy to fix by expanding knots away from each other in 3D using the scale function.
In having to also learn SolidWorks I’m suffering shock for how hard that can be. Trying to model a bowline knot, and in SolidWorks it often happens (more often than not) that the cross-sectional shape will distort someplace in the middle … and that the distortion will PROPAGATE all the way to the free ends … such that at one end, instead of a circle, I’ll end up instead with a polygon: hex, square, or even triangle … and these not even regular. It is proving exasperating.
Never in Rhino does anything untoward propagate out to the free ends of the spline far away and well clear of the kink. In SolidWorks, however, it does, in a way that is entirely unlike in the real world.
Has anyone here met the same problem? Can you explain what’s going on? Best of all, how to avid it?


Please post some descriptive imagery of the undesirable effect in SolidWorks. Hard to say without any information.


I won’t to appear rude, but you mistaken the forum.
this is rhino forum, why did you expect answer for a software made from another company?
ask they forum why such expensive tools doesn’t work as expected.
it’s much fair and simple.

  1. Free speech; adherence to forum rules
  2. Interoperability; many design studios must use more than one software
  3. Usage; many users here are proficient in more than one software
  4. Cost; even Rhino is expensive for a certain user base
  5. Right forum; the only absolutely right things are the four fundamental forces in nature and mathematical proofs

With that, it’s a perfectly valid question and the right forum.


I did get an answer on this. In SolidWorks, apparently, you simply can’t sweep as sharp a bend as I’m accustomed to doing in Rhino. And when things go wrong, it’s nowhere as easy to fix, either. Certainly not anywhere as intuitive as looking for the intersects and/or kinks, then calling 3D scale to move offending spline knots away from each other. Henceforth (my SolidWorks class being near finished) how always I’ll do this, is to first make my sweep in Rhino (which I’ve owned since version 4) then export just the spline itself via *.iges to SolidWorks. A huge time-saver that will be.
What I ended up having to do instead in Solidworks was to sweep a smaller diameter, then project a surface around it. Those kind of intersects are allowed, apparently. No bizarre profile distortions occurred. Since I was only modeling knotted rope, intersects weren’t an issue (in Rhino there weren’t any, and I got the knot fairly tight). The problem in SolidWorks was the intersects being so hard to fix, because I couldn’t see where they were. Nor was there an easy and convenient way (Rhino scale feature) for moving plural spline knots gently away from each other. Rhino forum or not, I think this is helpful to know.


Here is a link to the other forum where I did get an answer. Images and actual files (SW & Rhino, with readme) in a ZIP posted there. And down below, I also posted a verbal description of my experience. It is well for me to also learn SolidWorks; but I am very glad to have personally owned Rhino all of these many years.