Flow Along Surface Ring


I hope someone can help me with this problem.
I tried to create a ring along a surface, but was only able to select one fourth of the surface. So I simply split my solid object into four pieces to flow it along on fourth of the surface and mirror it afterwards.
The problem is, that I am not able to unite the four parts into one solid object. Reason for that seem to be small gaps between the objects.
So my question is: Are there better ways to create this ring or is it possible to unite the four parts somehow?

Thank you for your help

flow along surface.3dm (1.2 MB)

flow along surface edit.3dm (1.0 MB)

Is this what you are going for??
Take each half and explode.
Remove the interior surfaces.
Snap back together and join.

UGH… sorry I just noticed there’s a big gap along the bottom.

I removed the interior srfs from the 4 polysrfs. Join leaves naked edges. A series of edgesrfs works to close the gaps.flow along surfaceCK.3dm (759.2 KB)

Hi Mischka- there are two problems- one is, on the original object, you need to remove the end caps and the vertical surface that will lie on the centerline- all of the open edges left by this will be joined once you mirror the flowed object.

The trickier problem is that the target surface- (remove all but one of the target surfaces for now) is not the shale you think it is- that is, it is slightly non-tangent across the centerline meaning that the surface normals along the centerline so not all lie in the vertical mirror plane. Since FlowAlongSrf will map the verticals in the original (since they are vertical compared to the base surface, that is, aligned to the the base surface normals) to the target surface normals and these, not being on the vertical plane, will not map the outer edges together. I made an exaggerated “bad” case in the attached file.
To make the target surface work in this case, use SetSurfaceTangent and select the edge of the target surface that is on the centerline, then set two points in the Y direction. You’ll see some of the points move slightly in the middle row.

flow along surface_PG.3dm (1.2 MB)


Thank you very much.

It took me some time to understand the SetSurfaceTangent comand, but once I got it, it worked perfectly.

Can you tell me a little bit about the trouble you had. It might help me to improve the Help topic for this command.