# Plugin or Rhino Tool for Swept Volumes (Sweeping SOLID Bodies, not Curves)?

Hello, has anyone ever heard of a plugin that can create a “volumetric sweep” by sweeping a solid or mesh along a curve? It’s quite a different problem from “solid-sweep surface along curve”, which actually only uses the border of the surface–I’ve tried it. CATIA apparently can do this, e.g. here is a 2D simplification of what we want to do:

Also, SolidWorks and NX can do swept volumes, but only with “analytical geometry”, which they define as lines and circular arcs (what, Bezier curves aren’t “analytical”???) I’d like to use polysurfaces or better yet meshes…

Thanks,
Andriy

P.S. I have a hunch that it’s more complicated than this though…? For one thing, instead of the plane intersection, the sweep section should be a 2D projection? For another, as the curve bends, the 3D shape of the brep can carve additional volume out of 3D space?

Hey, thanks for trying to make it work, Joseph! Exactly, the volume portion out of the plane is the hard part, otherwise “extrude ‘surface’ [really just surface edges] along curve” would work. Really, I guess an algorithm would need to section the solid/mesh/surface to be “volumetrically-swept” with a sectioning plane that is normal to the curve and get the profile, then repeat this infinitely as the curve’s normal plane varies along its curving length, then loft all of these sections together…

There are actually a surprising number of applications to this, given that no program I’ve found other than supposedly CATIA can do it. E.g. you can see if you can remove or reinstall an engine block, ie. whether it has enough clearance to go in or out, by sweeping out the body of the block along the path it should follow. Also useful for machining, although most cutting tools are derivatives of lines & arcs so SolidWorks can do that…

“Surprisingly, XNurbs should perform in all scenarios! In fact, both XNurbs and Catia are powered by a technique called variational surfacing. The variational tech powering XNurbs is way ahead of others, and no other system can perform what XNurbs can do.”

vol_sweep_2018Apr8a.gh (11.7 KB)

Seems to work with a 3D curve as well:

P.S. NEVER MIND! It fails when most of the brep is hidden in the shadow…

P.P.S. In this specific case, you can connect the vertices of the oriented breps to get the enclosing volume, but it’s not a general solution that will work with all breps.

vol_sweep_2018Apr8b.gh (13.9 KB)

Ah, forget about it, it’s just a mess.

Thanks for the link Rickson, XNurbs certainly seems powerful, but it looks like it’s just an engine for creating surfaces with many constraints, like Alias but only up to G2 continuity. It doesn’t seem to be able to do volumetric sweeps…

That’s an interesting script, thanks Joseph!! Maybe I can get it to work, let me play around with it…

I got distracted with SUnion failure and forgot to post this - it gives a better view of the complexity of the resulting shape, but doesn’t ever “get there” as a smooth solid.:

vol_sweep_2018Apr8b.gh (10.3 KB)

Outstanding!!! That should be good enough for my needs. (As long as the Union operation works. Could also do mesh unions, they can be more reliable with other programs)