Noob Modeling Question

Hello Rhino Community!

I’m attempting to put a floral pattern under the railing of a spiral staircase. I currently have them curved horizontally but can’t seem to figure out how to make them corkscrew vertically like the railing does.

I’d like to note that I imported all of this from sketchup (not sure if that makes a difference). My thought is if I can’t get this to work, that I need to remake the whole staircase without any bends, and just have everything modeled like a straight staircase. Then just bend everything at once to match the curve I need.

Any help will be really appreciated!

You’ll get more help if you post your 3dm file…

Thanks, I had to delete a few things to make it a smaller file size, but here it is.

Stayer-Foyer-2017-For-Web-Upload.3dm (16.4 MB)

Hi Matt - if you have curves for the 2d, plan view - the arcs and straights - and spiraly 3d versions of these same curves, then Flow may be the tool to use.

If you have straight versions of these objects, you can do it all at once with Flow from a line to the 3d curves.

(But I do not see these curves in the file so far)


  1. Make stair steps on flat, rectangular plane.
  2. Use Sweep2 to make helical surface.
  3. Use FlowAlongSrf (rigid = yes) to copy the steps on the helical surface.