Unify surface normals for Nurbs Polysurfaces


Is there a command like _UnifyMeshNormals for Nurbs? (Not _Dir)



Hi Kev,

usually if you join Nurbs polysurfaces and surfaces into one part, Rhino takes care of the normals itself and orientates them automagically. Presupposed the geometry is connected and joinable of course.


(Pascal Golay) #3

Hi Kev- can you post an example? Rhino should sort out the normals of of joined surfaces automatically.



Hi Pascal,

test.3dm (211.2 KB)


Hi, Clement,

I attached a Rhino sample file :wink:


(Pascal Golay) #6

Hi Kev- how was that edge blend made, can you recall? The corner piece is there but not meshing because its edges are bad… If you extract that surface and UntrimBorder, it will shade correctly, but you can also see the surface is not very nice- rippled.



I don’t remember but I think I get it now. Thanks for the help…Works perfect! :wink:


(Pascal Golay) #8

Hi Kev- OK- it looks like maybe BlendEdge made this- I’ll see if I can reproduce it- meantime, here’s a corner piece and two curves - you can trim this into your object and have a little nicer (ripple-free) transition there.

CornerPiece.3dm (39.3 KB)



Hi Pascal,

Yup, the surface you created is nice… Did you _BlendCrv from two edges? I guess so…
You made me make an A-class surface. :wink:


(Pascal Golay) #10

Yes, exactly… Trim and then Sweep2 with the short edges as inputs. But we’d still love to be able to reproduce what you got, from scratch- I see that the revolved top surface is not quite large enough, if untrimmed, to reach past the corners of the base hexagon, and extending it followed by BlendEdge at 1.1 radius, which appears to be what you used, ‘works’ in that we are not getting that nasty corner thing. So, if you have the original inputs (pre-edge blend) and can send me that, it would be grand.



Hi Pascal,
Here is the demo how I made that part. ( I’m still trying to find the original file)

In the end, I used both _Filletedge and _Blendedge but I guess that time I was not satisfied with the both results (like the one in the demo) and I made some changes manually. By the way, why does filletedge result is better than Blendedge? Blendedge gives more control points also…

Edit: File upload
Fillet VS blendedge.3dm (317.9 KB)


(Pascal Golay) #12

Hi Kev- thanks- I am way from my desk for a couple more days this week, but I’ll take a look and get back to you.