BlendSrf doesn't work

I tried to blend two surfaces together but it gives me strange results. First I offset surface then want to blend them together. I choose first edge then the second one on the offseted surface and the 1 and 2 (sorry I don’t know how it is called) are not at a same height. I think this is what caused the strange results I mentioned in the beginning. I would really appreaciate any help. It’s been driving me crazy for hours now because I don’t know how to fix it.

You can click on the point for either 1 or 2 to move the blend point and get them more aligned. Once you have that were you want it, if it is sill misbehaving, you can click the Add Shapes button in the Adjust Surface Blend window to further define desired cross sections and make the blend more what you are looking for.


Hi Sonia - if you cannot get this sorted out, please post a file with your two surfaces. Someone will take a look.


Thank you both for answear :slight_smile: the problem seems to be that while choosing the edges I want to blend, a point on a curve I click on matters whether it will blend it properly or not. I don’t know if it is my file’s/geometrie/s fault or my lack of knowledge how the program works. I uploaded my file in which one hole while blending acts strange. If while choosing the edges I click on the top of the curve and then select second edge as well somewhere in that area it doesn’t blend properly. On the other hand if I choose points closer to the bottom it works more accurately. blend surface problem.3dm (1.2 MB)

Hi Sonia - the problem is that the seam in the inner surface crosses the hole and Rhino does not recognize the edges as forming a closed loop, so it thinks you are blending from a closed loop (outer) to an open set of edges (inner_ even if you select all the edges. The vertical seam is actually open, in fact. This is fixable but you need to jump through a couple of hoops:

  1. DupBorder on the inner surface. Explode the resulting curves and then join the parts back to just have the closed loops that are the holes. Delete the other curves that are left.
    2.MakePeriodic the inner surface, DeleteInput=Yes. Note the result looses its trims - retrim the holes with the curve you made above.

Blending should now work - what MakePeriodic did was make sure that the seam is a smooth closed seam on this inner surface. See Help for more info…