Non-Collapsing Ball of Yarn / Spherical Curves

Technical Support Particles and Physics Simulations
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1

Heyo, Blender Community!

I’m currently working on a project to make a ball of yarn bounce. I modeled yarn using this tutorial (TL;DR: use a few spherical curves overlapping at different angles.)

Now I want to make it bounce like a ball. I have a sphere (cube with subdivision modifier) inside of it which I added soft body physics to which does it correct motion. However, the sphere itself always collapses.

yarn_mesh_collapse_on_bounce
yarn_mesh_collapse_on_bounce418×233 53.7 KB

(Pink is the outer yarn that collapses on collision, white is the sphere that bounces back up.)

Was wondering if anyone had any suggestions on how to keep the yarn / spherical curves shape while having same physics as the sphere. Any tips or pointers would be much appreciated!

Things I’ve tried:

  • Joining the two meshes together using join, parent, and boolean. This generally either kept the collapsing behaviour or caused the sphere to collapse as well. (Note: for some of this, I converted the curves into a mesh and decimated it)
  • Tried increasing the pressure with a cloth modifier. The shapes of the yarn kept in place but it “unravelled”
  • Tried turning on self-collision (both with soft body and with cloth), yarn would disappear, I think it couldn’t render. I tried using the decimate modifier to scale down as much as I could.

I’m currently using Blender 5.1.1.! Thanks!

2

Since as a newcomer, I’m only allowed one embedded media per post, also wanted to add what the mesh looks like so you don’t need to go to the video.

yarn_mesh_better
yarn_mesh_better584×487 186 KB

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Hi, i think as you already found out this wouldn’t work. i would just use textures or sculpt it?

4

You may try to some ball bouncing simulation with a (ico)sphere and then simply use some object constrains (copy location, rotation) to you “special model”..

5

@blenderjazz

Hi,

Do the cloth sim on a sphere . . .

Then add a SurfaceDeform modifier to your ball of yarn, and press the BIND button after assigning the cloth sim ball . . . they should be roughly the same size, The yarn mesh can be ‘inside’ the cloth ball it will still deform.

image
image2569×638 315 KB

The result . . .

Cheers,

Dj.