Hi all!
I’ve been trying many definitions and trying to adapt them but so far had no success what so ever.
What I need to achieve is shrink wrapping a cylinder around an helix basically. I’m modelling a lamp that’s made out of paper around a spring.
I don’t know how to insert images or files here sorry.
DESIRED OUTCOME
There’s still ways to improve this but it should be a good start to get you going.
lampion.gh (28.8 KB)
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Thank you so much for this! Amazing to see, it seems like I can take this as a basis somehow.
That’s the closest I got using a sweep on a straight section that I then bent in Rhino. sadly it doesn’t give me any control on the shape. That’s why I’m trying another way which is “draping” the paper around the helix.
https://i.postimg.cc/Y0vTZqb8/Screenshot-2022-08-21-203626.jpg
Blender has a modifier call shrinkwrap that takes a brep (a cylindrical surface in my case) and wraps it around a “target” (the helix in my case). I can maybe adapt what you did to get something similar?
So here’s where I got to.
The outside tube is shrinking in the right direction and the points stay out of the solid but don’t stop there. Could I use the faces instead of the points? Can anyone get me out of this deadend?
Thanks 
220822_kangaroo_tests.3dm (10.4 MB)
220822_kangaroo_tests.gh (20.4 KB)
Here’s another example.
I hope you are starting to see a pattern. First you construct a strategical mesh, then you use it to simulate shrink-wrapping or rather mesh relaxation with constraints.
lampion-helix.gh (26.6 KB)
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Thank you so much @diff-arch !
I do see the pattern now -learning so much right here!
It’s looking very very good but I don’t think I can get the right result using that method.
Anchor points don’t match the solid wire, when I try rendering it, the wire pops through the paper. It feels like the mesh should wrap around the solid sweep of the wire and not “just” deform randomly along the helix. Maybe I should look at using a pressure goal or a soft mesh collision?
I really need to try and develop a definition that can be used as a tool for my lamp making, i.e. ideally inputting a helix wire mesh of any length/revolutions/step/thickness and a cylindrical mesh around it that the kangaroo definition could then “just” shrink. Then I could get physically realistic results that I could render and use as a prototyping solution.
I had some success for a straight section by just modelling the paper. I can’t do it for a bent section though.
Maybe grasshopper isn’t the right tool for the job, but I don’t see how else to do it.
Thanks again.
220822_kangaroo_tests_collision.gh (11.3 KB)
test wrap.3dm (5.9 MB)
It’s a simple demo. You have to make some changes if you want it to interact with a piped helix instead and do other, more advanced stuff. With peace and love, the problem with milking the forum is that you don’t really learn anything. You need to put in the work yourself.
I doesn’t deform “randomly”. It kinda simulates finding points on the base mesh that are closest to reference points on the helix and those are anchors, thus simulating hard local friction or supports. The other vertices can deform since they aren’t supported.
The acting forces are uniform, much like they would be in a material like paper.
This is more akin to what I imagine happens when Asian paper lanterns are fabricated, since they are made of strips of paper that get glued to the structural wire. There’s really no shrink-wrapping involved.
Seems like you want to take the easy, even less physically accurate route. Simply try it. Learning by doing is the best approach!
Harder things have been accomplished with Grasshopper though.
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Thanks once more @diff-arch for your thorough answer.
My intent wasn’t to milk the forum, sorry if I gave you this impression. I respect and am thankful for your help. I guess, although I find grasshopper fascinating, I was trying to sense if it could be used as a tool for me, in a “real-life” scenario. I realize that given my current skills set and my limited love for seating in front of a screen, it’d make more sense to actually make mockups and photograph them.
I’m looking forward to try and improve at that amazing software though.
Cheers.
Thanks @jeremy5 !
Did you bend a straight sweep? I f that makes any sense haha.
You guys are really impressive.
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Hi Alric,
- I made a curve to control the overall layout of the object.
- I created a helix using the AroundCurve option.
- I used Pipe to fatten the helix and get the wire.
- Another helix, carefully set so the starting radius hit the outer edge of the pipe.
- Copied the helix to another layer so I had two distinguishable but coincident ones.
- Trimmed one helix so it ended one turn before the end of the wire. Trimmed the other helix so it started one turn after the start of the wire.
- Drew a line from the start of one helix to the start of the second.
- Rebuilt the line with 7 points, degree 5.
- Used the gumball, oriented to the line, to move the middle three points inward a little.
- Swept the resulting curve, using the two helices as the rails, giving the covering material.
HTH
Jeremy
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@jeremy5
Thanks a lot, this is indeed very helpful! The solution is quite elegant and I feel confident I can make it parametric. It’s also a solution I can use on a more traditional CAD software.
@anon39580149
Thank you so much, I was doing something similar based on what Jeremy offered. You were much faster than me obviously!
I understand it’s not as physically realistic as going the kangaroo route as @diff-arch demonstrated. It will be easier to implement and use in my practice for the time being though.
I wish I can return the favors someday.
Enjoy your day everyone.
Alric
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Amazing @anon39580149 !
I’m missing an element here →
I managed to make the earlier version work by replacing it with an helix tool but it won’t work this time…
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