How to wrap objects around a cone?


#1

Dear all,

I’m desperately trying to wrap objects around a cone without distortion along their x-axes - they are cables placed on a cone shaped structure:

how can I achieve this?
Thanks a lot!

Cyana


How to wrap objects to a surface without distortion?
#2

Couldn’t you just use project?

http://docs.mcneel.com/rhino/5/help/en-us/commands/project.htm


#3

Thanks a lot for your reply. Unfortunately, projection does not work because it gives me a projected shape of the object on the surface of the cone, that is distorted as well (and I can’t create a matching 3D object from it).

What I need is to place cables with a rectangular profile (2x1") onto a cone shaped surface:

As you can see, the horizontal part of the red cable is far to wide (around 4" instead of 2") when using projection or surface flow.

I need to distort the base object somehow, so that it gets thinner with its height to correct the surface flow behavior, but I have no idea how to do that in Rhino (in 2D graphics applications like Corel this would be easy)

thanks
Cyana


#4

Okay, what about breaking the operation up into managable chunks, so you extract the “path” of your cables and project that onto the cone and then use the cable cross section to do a Sweep1 for example?

Alternatively extracting the edges of your shape and using Sweep2 will allow you to “maintain the height” of your cross sections.


(David Cockey) #5

UnrollSrf the cone

Place the objects in the desired positions along the unrolled surface

FlowAlongSrf


#6

@Artstep
thanks for your suggestion - I’ve tried it but the result is quite strange - while the shape is consistent, the resulting objects are twisted and thinned out.

@davidcockney
thanks for your reply. I’ve tried this already (actually, that was my first attempt), but it did not work for me. The objects were distorted in the same way as in projection and the lateral approach.

I finally found a way to do it with cages, but it is a painstaking process. Create the object first, then treat it with the cage, then wrap it. So if someone has a more elegant solution, that would be fantastic.

thanks a lot!
Cyana.


(Pascal Golay) #7

Hi Cyana - try:

  • UnrollsSrf the cone. Place your curves.
  • CreateUVCrv from the unrolled surface and the curves.
  • ApplyCrv the result to the 3d surface.

RollUpCurves.3dm (101.5 KB)


#8

Dear pascal,

many thanks for your example!
How do I create 3D objects from the applied curves? They should have a thickness of 1" parallel to the surface of the cone. Sorry if this question might sound dump, but I did not find a way to ‘fill’ the space between two parallel but curved planes. Otherwise, it’s exactly what I was looking for.

thanks
Cyana


(Pascal Golay) #9

Hi Cyanna -

  • Extrude the UVCurves star etc shapes (distorted but flat, red in my example)
  • Make a PlanarSrf from the surrounding rectangle from those curves.
  • Make sure the U,V and Normal directions match on the two surfaces - use the Dir command and the options there to align U (red) V(green) and Normal (white) so they match up relative to the shape curves.
  • FlowAlongSrf the extruded shapes from the plane to the cone.
    RollUpCurvesPlusFlow.3dm (200.0 KB)

-Pascal


#10

Hi Pascal,

again, thanks for your example and your efforts!
I’ve tried your solution, but the objects again come up distorted, also their top and bottom planes are missing.

I’m sure I’m doing something very wrong here?
best greetings and thanks!
Cyana


(Pascal Golay) #11

Hi Cyanna- can you please post what you’re working with in a Rhino file? I’ll see if I can sort it out.

-Pascal


#12

Thanks a lot Pascal - I’ll put it together! Please gimme some minutes!

best greetings
Cyana


#13

Hi Pascal,

I’ve uploaded a zip file onto my webserver @ http://www.microartwork.com/LUT/ThrustStructure.zip

Some explanations:
This will be a 1/96 paper card model from the Saturn V
I’ve included a picture from the thrust structure of the second stage I made at KSC were you can see what I’m trying to achieve. The cabling is done with .5mm thin paper strips that map to 2x1" profiles in real size.

On opening you’ll see the model - you can turn it off when hiding the trust structure layer
Ebene 1 - various attempts of wrapped objects
Ebene 2 - my attempts with cage editing
Ebene 3 - my attempts with your solution

best greetings and thanks!
Cyana


#14

Hi @Cyana,

If you manage to wrap/flow your curves into the cone surface, you can try using the ArrayCrvPLUS plugin to create your 3d profiles on surface without distortion.
(scroll down the page for download and some tutorials - seems like it could be handy with your type of projects).

–jarek


(Pascal Golay) #15

Hi Cyana - can you export the cone and the curves as a single small file and post that?

thanks,

-Pascal


#16

Hi Pascal,

thank you for your efforts!
I’ve prepared a small file now with fresh examples.
I could sort out the missing top and bottom planes of the objects, this was due to a slightly incorrect placement on the reference plane so that the objects were truncated at their bottom.

However, the distortion is still there.

ConeTest.3dm (1.2 MB)

many thanks!
Cyana


#17

Hi @Jarek,

thanks for your reply! Very cool web page!
I’ve watched the introduction vid, when I get it right it allows you to place multiple copies of an object along a profile line (?) - so not sure yet how to wrap an object around a cone surface, but I’ll give it a try anyway, this plugin looks very cool.

best greetings and thanks
Cyana


(Pascal Golay) #18

Hi Cyana - in this case you need to ShrinkTrimmedSrf the 3d cone before FlowAlongSrf. Also, Cap the extrusions if you want them closed.
ConeTest_PG.3dm (601.3 KB)

-Pascal


#19

Hi Cyana, the functionality I thought you may find useful is you can use curves on surface as paths and then use profile curves (rectangle shape) to loft between them along the path curves on your surface. You can do it with many of them at once. Not sure if this would apply for this particular case, but looking at your work I thought I’d mention it.

So for the above, you’d need to ‘flow’ just curves (no distortion is problematic then) and then use rectangular profile and your cone as base orientation surface to loft…

hth,

–jarek


#20

Hi Pascal,

this works perfect!!! Many thanks for your help!!!

best greetings
Cyana