Stretch fabric over wire frame

Rhino Rhino for Windows
1

Hi,
I am working on a stretch fabric lampshade using same construction as attached images
Stretch material over wire frame
Stretch material over wire frame 2
…
I’ve got my metal frame in place but not sure which tools (and in which order) to use to create the stretch material over wire. Any guidance please?

Thanks, Nancy

2

Hi Nancy - please post a file with one of the frames or a couple of sections of it, I’ll take a look . If the work is confidential, please send to tech@mcneel.com with a link back to this topic in your comments.

-Pascal

1 Like
3

Hi Pascal,
Have sent file with link!

Thank you!
Nancy

4

You can simulate this with Kangaroo

1 Like
5

Unfortunately I don’t have Kangaroo (or know how to use it) :slightly_frowning_face:.

6

Bad luck

7

Kangaroo comes with Rhino. As Martin mentioned, you can pretty easily build a lamp shade generator with Grasshopper and Kangaroo.

Screenshot 2021-09-28 at 21.37.16
Screenshot 2021-09-28 at 21.37.161110×702 181 KB

8

The attached definition works for convex frame sections.

You can set a separate tension for the mesh and the naked edges.

image
image1920×560 73.5 KB

kangaroo_stretchy_fabric_light.gh (37.3 KB)

2 Likes
9

Thanks for this Martin… I’ll have to learn Grasshopper / Kangaroo if/when I get time!

1 Like
10

Ok, thanks. I clearly have lots to learn (just need to split myself in two to do it :sweat_smile:)!

11

There’s really nothing to stop you from doing this in stock Rhino! You can simply:

  1. Draw one of the wires that form the frame - use nice simple/clean curves - ideally single span.
  2. Use ArrayPolar to populate the rest of the wires.
  3. Loft between two adjacent wires, use the Straight Sections and Do Not Simplify
  4. Use ChangeDegree to change the surface across the loft to Degree 2 from Degree 1.
  5. Grab the center verts and push them inwards.
  6. ArrayPolar the result.
  7. Blend or Fillet the sharp edge between adjacent patches.

Literally hanging over my head as I type this:

PXL_20210929_163656224
PXL_20210929_1636562241920×1440 91.8 KB

-Sky

1 Like
12

Yep - something like that is exactly what we came up with for the user-

StretchFabric.3dm (313.5 KB)

-Pascal

1 Like
13

Two different approaches:

a) Create a surface with the desired shape, using knowledge of what the shape should be. See SkyG’s and Pascal’s posts for examples.

b) Estimate the shape which will result using the geometry constraints and the material characteristics. I assume this is what Martin is suggesting. This is a much more complex problem.

14

As always there are many ways …