Hey there, i would like to make a smooth transition as shown in the pictures. However it seems that i lack some knowledge / tricks to make this work. I am familiar with BlendCrv, NetworkSrf and the difference between Position, Tangency and Curvature. I just don’t know how to solve a 3-side polygon hole…
3part_transition.3dm (86.8 KB)
Hi Andreas - please post a file with the objects. I’d say the triangle can be a plane, in theory, but it looks like it is not.
-Pascal
oh right, i attached it to the first post.
In fact its not a plane plane, more like a bent triangle.
It doesn’t have to be a triangle. I just don’t know how to do this.
another attempt, but not working:
Patch works, but the transition isn’t really nice.
Well, It’s a cheap way out but Patch does OK here - you need to duplicate the curved edges as curves for the input and use the straight surface edges directly.
@andreas6 - here is my go at it with just a patch
3part_transition_Patch.3dm (139.5 KB)
-Pascal
yeah, thats the cheap trick, i mentioned it already. But to fulfill my needs for proper renderings there has to be no visible “edge” at the transition.
Edit:
I nearly got where i want.
if there is a better / cleaner solution i would welcome it.
A different approach which needs some control point location refinement:
3part_transition_DC01.3dm (2.2 MB)
The chamfers were rebuilt so that the ends are isocurves.
IMO you are working too hard using a triangle- The singularity will fight you till the end.
I’d go for more something like this.
right about now @sgreenawalt as the master of nurbs topology should show up and tell us how we are all doing it so very wrong…
With two surfaces something like this:
@Rhino_Bulgaria has also made a video of this approach:
You can also try this approach in case that you are aiming for a nearly Class-A surface quality with clean surfaces. But keep in mind that it’s slow. The quick “dirty” approach is already shown in the port above.
Thank you all so much,
i will dive into this for sure, class-A surfaces are definetly something i want to aim for and the videos are indeed what i was looking for.
@theoutside yeah, i was guessing that triangles aren’t the proper solution although it seems too obvious to use them 
