Problem using flowalongsurface tool. Help please!


I’m a university student and I’ve been working on this chair design for injection moulding. I’ve been trying to apply this line drawing which I drew in Illustrator to the back of the chair using Flowalongsurface but unfortunately I’m not getting anywhere and I’ve been at it for hours.

When I select the back of the chair without using any command - it selects as a whole:

Yet when I use Flowalongsurface, it will only let me select a small portion of the polysurface that I want it to flow along:

And I end up with this result:

Rather than the line drawing being applied to the back of the chair, it’s been moved to an undesired angle. Would you happen to know why that is? Or how I could possibly fix this?

Would much appreciate any advice or help!

Thank you,


Hi Octavia - the chair is made up of many surfaces joined together into a polysurface - this is most likely a scan of a chair that has been auto-surfaced, or something created from a polygon mesh and surfaced. It is far from being an ideal way to represent the shape, but but in your case it is extra un-helpful because of the FlowAlongSrf question - this command works on a single surface at a time, that is why it is only letting you select the little bit - one surface. If you can post the polysurface that is the back of the chair and the curves, it should be possible to trick rhino into doing something useful here, maybe, but it is not a good case for FlowAlongSrf.

I may or may not get to this quickly, I am out of the office a good deal this week.


Thank you very much for your help @pascal. I really appreciate it!

Here is the file for the polysurface and the curves: Patternchair_1.3dm (2.4 MB)

Thanks again!


Hi Octavia - here is a surface approximation of the chair back. The curves are mapped from the flat plane onto this surface. You can manipulate the flat curves or the flat plane (Base surface) to edit how the curves lie on the chair surface.

Patternchair_1_PG.3dm (2.8 MB)


Thank you!! @pascal