Wanted: rail revolve with two rails (or workaround)? A little challenge


I need a single surface to animate it and theoretical rail revolve with two or more rails would be the solution. But rail revolve supports only one rail. Is there a way to get the wanted result?

Best -

Best with more curves:

Post a .3dm file with the curves.

Split the straight top segment from the other part of the section curve.
Sweep2 the section curve. Use Slash if needed to control how the curves are joined.
Sweep2Example.3dm (2.0 MB)


Thank you for your suggestion. I checked your example and I don’t see how I should close the upper missing cap and to get one single controllable surface.

I did a new test and used the standard rail revolve with one of the upper rail curves. So, the lower end wasn’t a circle but I manual moved the control points of the lower edge to a circle shape. This is the result - a quite simple and basic NURBS surface, but not perfect. I wonder that it is not possible to create such a simple surface on a direct way and with clean result. Why the rail revolve doesn’t support multiple rails?

I tried network of curves, but it doesn’t work. Is there no Rhino command which allow to create such a single surface?

Here a file with curves:
Revolve.3dm (41.9 KB)

Hi Micha -

We have that request on the wish list as RH-1786. I’ve added this thread.

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If the object is symmetrical you could revolve only half, then mirror, stitch the top, join and cap.

Could I get a single surface this way? I don’t know so much about modeling tricks and when I try to get single faces by multiple faces I had no luck.

I missed the need for a single surface.

Cap created using loft from the edge of the side to a center point.
MergeSrf the side and the cap
Sweep2ExampleSingleSrf.3dm (1.8 MB)

Another example using smooth curves:
Sweep2Example2.3dm (1.8 MB)

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hi maybe this solutions by (sweep2rail Point) by Flexibility.Gh plugin
help you ! in grasshopper the results is single Untrimmed Surface
and you must bake it to Rhino!

railrevolve multy sweeppt.gh (14.9 KB)
_so rail revolve multiple rails is very necessary to add in Api and Rhino and
Sweep multiple rails


Revolverh6.3dm (714.6 KB)

i think a simple approach is to
clean up the top surface
_selU to select control point rows
_setPt to make the top planar (z only)
_setPt to create the pole (x,y,z)
_selU delete a messy row
_insertControlpoint to have initial amount of cvs

another approach with maybe more control would be to create several horizontal curves and then loft them.

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