I need help with Blendsrf

Hello. I’m beginning student in Rhino 5. I was following the tutorial offered by “Rhino 5 User’s guide” (which can be downloaded at Rhino3d page), and I got problem with Blendsrf command.

I was making penguin in 3D, and I had to use the command to connect a couple of surfaces. (I mean blending tail and body. it was at Guide page 130.) But I could not. when I used the command, It didn`t work.


the result of Blendsrf in the guide was like this, but I just couldn’t do that. I thought I did not fully understand the method of using the command, so I checked the help offered by Rhino software, but I still could not understand.

Could anyone tell me the proper way of using Blendsrf? I am uploading the screenshot of the point where I got trouble. thanks!

Can you upload the file or post what happens whle you are using the command?

Are you able to select the two edges?

Hello there. Thanks for answering my question and I`m sorry for replying late.


This is link for the video file of “What happens when I use Blendsrf”. I could select two edges, but eventually the attempt to make smooth surface blend was impossible. It would be nice if you tell me what is wrong.

p.s. My Rhino client is Korean. I apologize in advance that I am not in situation to install English client now. I`m terribly sorry. If you have any question about what the words in the video means, please feel free to ask. Thank you.

I see there a gap on little sphere edge, have you already used MergeEdge on edge of little sphere?

Hello, and thanks a lot for advice. Was there a gap on that small sphere? I could not recognize that. Could you tell me the specific location of it?

In addition, I overlapped two spheres, made pipe with the edge made by two spheres’ boundary, and applied boolean to trim those spheres, and those were command I used. Was there any additional error you can see? I’m just a beginner, so I think I can barely find them. Thanks again.

At second 14, when you select the edge of the small part, there still a portion of the edge that is not selected,
that means the edge is split.
Use the command MergeAllEdges and select the small part and hit Enter
Now try BlenSrf again and see

Hello, and thanks a lot! :slight_smile:
I finally found the problem thanks to you guys’ helps! (How did I see that now? That gap was not hiding at all…) I’ll merge the edges first and try blending again. I think it will work.
Thanks again to your help.