How to Converge three different organic sweep shapes at single point?

Continuing a bit from the previous one… but little more organic…
Trying to create a part where three different shapes coming into one and have a smooth surface…

Below is somewhat of the target shape, but… not at all looking like a finished shape…
trying different things… at it for hours…

Connecting_Three.3dm (640.2 KB)

There might be some hints in this video by @BrianJ New tutorial: Modeling a bubble R

Thank you.
I gave a little more room for the blend. Now changed to networksrf.
Also put some blendcrv between isocurves for the networksrf…
kinda getting there…

Connecting_Three_v2.3dm (687.2 KB)

Do you have links to jewelry design or organic things using naked rhino?
Also is there any info if when tsplines and other plugins will be coming?

came to making up to here, but
thinking of way to make the center part into non-planar and a little more round so the surface
looks more like one…

Any tips, any direction to tutorials are very appreciated!

3to1point.3dm (564.7 KB)

Would this help?

Thanks for the link.

It sort of worked, but I couldn’t networksrf the 6edge part, so split it up and networksrfed.
Still some bumps here and there…
I may have messed around too much…

3to1point_v3.3dm (575.6 KB)


i´ve used only _BlendSrf with some tweaking, then matched the edges using _MatchSrf with the _Multiple option. The middle surface is just a _Patch using the remaining hole edges and some _Blend curves to guide it. See Layer “Helpers” for more info and evaluate the result with _Emap:

3to1point_v3_cg.3dm (487.9 KB)


very nice!
I’ll try it out. Thanks a lot!
So many tricks to learn!

Hi Clement,

Just to make sure, something like below just about right?
After using pipe to cut off the sweep2 surface to get some room:

  1. SplitEdge of trimmed off sweep2 to get smaller edge for blendsrf.
  2. Matchsrf to get the blendsrf side to meet with outer sweeped surface(three surfaces).
  3. Closed up the 6sided opening using patch. with some guides.

(I didn’t know you can select curves as guides when using patch till now!
I didn’t like patch tool, but now looks like a nice tool.)

Edit:Updated file since previous had some naked edges in the patch
(did not have adjust tangency box ticked when making)

3to1point_v5_update.3dm (505.8 KB)


i did not use _Sweep, only _BlendSrf. The first i did where splitting the edges at the 3 red arrows in my file. Then i created the 3 surfaces marked with an “A” using _BlendSrf using Curvature option. While the _BlendSrf preview was active, i´ve tweaked them using the handles provided to stay as close as possible to the existing geometry. Then every of the 3 blend surfaces marked with an “A” where matched on 3 sides using _MatchSrf and the _MultipleMatches option. In the _MatchSrf dialog i´ve chosen Tangency, Match Edges by closest Points, Refine Match and Preserve Isocurve Direction. Next step was to create the 3 pipes, then Split the 3 Blends with them. This is to make room for the blends created in the next step.

I´ve created the 3 other blends to connect the 3 blend surfaces marked with “A”. These 3 where also matched to the short naked edge of the main part near the 3 red arrows. Finally the remaining hole was done with _Patch using the 3 _Blend curves to guide it (of course using Tangency). These 3 curves where created using the _Edges option in the _BlendCrv command.

Btw. after every _BlendSrf command, i´ve selected the result and used _RemoveMultiKnot. Most important is that you tweak the blend surfaces using the handles while it is created.


1 Like

Hi clement,
Thank you for the detailed explanation.
Especially the settings you used for the commands.

One question about patch, I sometimes get naked edges or not being able to trim.
Is there general don’ts when using patch?
I kind of fix it by making used curve having less shap angles, but it’s an trial and error kinda way.

@Toshiaki_Takano, for the patch surface to be joinable make sure to select the outer edges (they must form a closeable border for trim to work) then the inner blend curves and increase the U and V Spans. I Used 14 for UV Spans and Sample point spacing of 0.6, Stiffness 1.


Thanks again for the settings and the tips.
I’ll test them out.

Thank you everyone for the good tips!
also to @jim from previous thread.

Got it working up to here. Still need to work on getting simpler surfaces and
some places I’ here and there, but getting there.
Thanks again!