Flow along surface problems

I’m trying to flow a polysurface on to a surface.
I unrolled the surface to create a base surface and built the polysurface to the same size.
When I flow the polysurface everything works fine, except that I get “cross” surfaces on the inside of the target surface. The target surface is a closed ring.
Any ideas why this is happening?

Hi Iftah

If you can post a rhino file (or even an image) with the objects involved it is much more likely to find the cause.
Without seeing the actual geometry it is just guessing what could be wrong.


Hi Willem,
Thanks for your reply.
Sorry for not attaching the file, here it is now.

Hi Iftah,

Based on the image I think this has to do with the surface to be flowed being distorted at the seam of the target surface. Without the actual file at hand it is hard to tell the exact cause. But it could be either the flowed surface or the target (ring) surface are slightly “off” causing the distortion.

In this case I would suggest to work around this:

Instead of modeling a complete strip to be flowed, model just the letters/characters that can be booleaned out of the solid ring (you will need to model the ring as a solid ring with thickness)

Next flow the solid characters from base to target (ring) surface. Then use the flowed characters to boolean out of the ring:

Notice how you can also use the ridgid option to create less distorted flowing.

Also you can FlowalongSrf with History enabled, that way tiy can adjust the base objects on the flat plane and their flowed couterparts will update on the ring.


Hi Willem,
When I flowed the letters I noticed that the surfaces get distorted so I checked and the curves that I made the letters from cross each other, so fixing that fixed the problem.
No the question is if there is a easy automatic way of locating these problem areas along a polyline that will cause this problem?


P.S tried to upload the file but it doesn’t want to work.