Joining open and closed surfaces?

Rhino
1

how do I join closed surfaces to an open surface OR do I need to convert the open surface to a closed surface?? thanks!

Art

how to save open and closed surfaces
how to save open and closed surfaces2143Ă—1611 252 KB

2

Can you send the files to us? Join should just work, but we can look closer.

3

the “join” challenge has morphed into an “explode” problem! in search of bare edges for “join” I’ve encountered a closed collection of surfaces that will NOT “explode”. as the creator of the closed collection of surfaces I have NO idea what’s going on or why. any thoughts or ideas would be greatly appreciated??

Art

explode problem
explode problem2142Ă—1611 244 KB

explode problem.3dm (444.9 KB)

4

Groups need to be Ungrouped (its a selection set vs a joining of geometry or blocking of)

5

Thanks!! that’s got it; I have a free edge to work with…

Art

6

feel like I’m chasing a strings with too many knots… how do I join three surfaces at a common free edge (ie: a T-joint) ?? thanks again for your help and patience! see collage and file attached

joining question 2
joining question 22143Ă—1612 327 KB

T joining question.3dm (598.7 KB)

7

I’m writing a new course and this just came up. A better way to think of any join:

  • Two curves must share end-points to join.
  • Two surfaces must share an edge to join.

If the surfaces are not joining, then (1) Make sure they overlap and (2) trim or split them to each other. Since they now share an edge – where the intersection occured – they will join. Boom.

8

Dave-

thanks for the quick reply! completely onboard with joining two lines and two surfaces! the situation I have seems different… removing the lower surface of the horn leaves two free edges. using the horn to create a matching hole/free edge in the surface leaves a hole/edge that matches the outside of the horn. joining the outer free edge of the horn to the free edge of the surface leaves a free edge on the inner surface of the horn…?? the extra free edge is my problem…

Art

9

Three surfaces joined at a common edge is a “non-manifold” polysurface. Rhino doesn’t like non-manifold polysurfaces though it sometimes tolerates them.

You can create a non-manifold polysurface using NonmanifoldMerge
“This (is) generally only useful for export to analysis programs and can cause normal Rhino operations on these objects to fail.”

10

David-

Thanks!! in this case CFD…

Art