How to Bridge two PolySurface Edges?

This should be easy, but since I’m a noob still, I can’t seem to figure this out. I just want to ‘bridge’ (as it’s called in Blender and other software packages) the two holes you can see in this image:

…so that I end up with a tube connecting them together. I can either extrude one edge to meet the other, or select both and do a loft, but the tube that gets created is separate from the other two objects (and after I do an extrude or loft, I can’t boolean them together).

So how can I accomplish this? And a more general question I have is: why when you extrude a polysurface edge is the resulting object separate from the ‘source’ object?

So I ended up using a loft to create the tubes, then closed off the caps before doing a boolean merge between all three parts and then deleting the caps I had created on the ends of the tube.

BUT-- in ‘rendered’ view, you can see faint ‘seams’ where the edges of the tube meet the two objects on either side. How to get around that?


HI @Bryan_Green, I only have a sec to reply for now, but I figure something is better than silence–

There are multiple ways to accomplish this, but since you’ve gone down the Loft & Boolean path, the quickest thing for you at the moment might be:

BlendSrf is another method. When selecting an edge which is the edge of two surfaces, be careful to select the edge corresponding to the surface you want to be tangent to.


not sure for which result / workflow you re exactly asking - but _extrudeSrf (delete input = yes) should do what you expected.

for your initial question:
did you try to _scale1D one part and delete the other ?
(assuming that the 2 surfaces are parallel ?)

if you need more input post the file.
if you like one of the answers, mark them as solution.

kind regards -tom

I think @Bryan_Green was possibly referring to the fact that the new extrusion doesn’t act as an “extension” of the original polysrf - i.e. it doesn’t automatically boolean-union.

Hi Bryan - it seems you are thinking in terms of solids - you can do that, often, but it can be helpful to deal with objects as surfaces - Rhino lets you explode and rejoin objects as needed.
(though, it is not clear to me what solid you want to end up with, from the image above - does the tube have a wall thickness, or? Can you post what you have?)


Correct-- in other 3D packages, when you extrude you are creating a continuation of the surface, so I was expecting the same behavior in Rhino. :slight_smile:

check _extrudeSrf
as posted above