Difficult Shape Modeling

Hi rhino community!

I was tasked with this job about two months ago and didn’t come up with any solution to this day. Basically it’s a extra link that needs to be added to an existing bracelet that was a little to tight on the wrist.





As you can see it has a very caracteristic shape that ( for my skills in rhino) it’s kind of hard to model.
Now…i tried to model some of the basic curves and tried to shape some surfaces out of them, but i always get stuck with some kind of surfacing problem due to (probably) the strange arrangement of the curves.
Thanks in advance to anyone who helps me!

17.3dm (407.9 KB)

I know someone who would do this by hand and you would not be able to tell again which was the added link, it doesn’t make sense to me to reverse engineer this just for 1 link.
But that being said I think the first step is to make sharper images and a drawing with accurate dimensions. Looks like this shape is very well suited for subd modeling

Hi, @simon_falze

This would only be an idea of how you can address this problem.

  1. create a set of curves as in the example image.
  2. then use the NetworkSrf or Sweep2 command.
  3. split both surfaces and join.
    I’m sorry for not uploading the file, I was doing another job at the same time which produced an error and I had to close everything; failing that, I lost this exercise. :cara_neutral:



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Hello guys sorry for the long hiatus,

first of all thank you for responding to this thread and helped me out but to be honest i’m not quite satisfied by you’re solutions.@vikthor your strategy is interesting but it isn’t a very precise way to do it (i think) and it doesn’t give enough control over the surface, it’s probably faster but i then wouldn’t know how to modify it to make the desired shape.
I recently re-started to work on it and found a way to get the main shape of the link


It may not be the cleanest surface modelling of all but i think the results in the zebra analisys are accetable. (let me now what you think and if it can be done better)

Now i have problem (again :frowning:). I don’t know how to make the trasversal cut


I tried to create a surface from a set of curve that pass through it and then cut it but the result is quite bad. Thats basically the only way that i came up with to do it.

If you guys would like to help me ill’drop the .3dm down here:
GP.3dm (915.3 KB)

Hi Simone, I am a watchmaker and work with a couple of jewelers. This would probably be better done by fabrication.

As to doing it in 3D I could have done it in Studio Max years ago with mesh editing and a very fine mesh. Rhino does not seem to like working with mesh much at all. I am looking at various programs right now to find the best one for doing 3D printing. Rhino has a lot of positives, but I have run into some rather problematic items that should not be popping up with the simple tests I have been doing.

Hi @simon_falze, still I think if this is just about creating one link, replicating one link through traditional methods would be the fastest solution. Having said that, I couldn’t resist to send you a rough subd approach. It has by no means perfect topology, but maybe it helps you
GP-subd.3dm (127.8 KB)

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WOW!
I’m speechless
Sub-D uh? I really need to look more into this. In the first response you gave me i wasn’t understanding when you said “use Sub-D modeling” because i didn’t know, and still don’t know, what is it but now i see the potential.

Thanks a lot for your time spent modeling this, it really opened my eyes

have a look here:

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Incredible! So they’re tweaking it already in the upcoming Rhino 7…That means that if i learn it now i then would need to learn it again when Rhino 7 releases :frowning_face: :frowning_face: :frowning_face:

I wouldn’t say tweaking. SubD is a completely new set of tools within Rhino 7. The subd tools in v6 are not officially supported. But if you have v6, you can dowload the wip and start learning today.

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