# Colliding Inflating Bubble and Anchored Cloth/Rope

**URL:** <https://discourse.mcneel.com/t/colliding-inflating-bubble-and-anchored-cloth-rope/215932>\
**Category:** Kangaroo\
**Tags:** windows, mesh, grasshopperrhino, inflatable, collision\
**Created:** [February 14, 2026, 9:44pm UTC](https://discourse.mcneel.com/t/colliding-inflating-bubble-and-anchored-cloth-rope/215932 "2026-02-14T21:44:46Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Ing\_F](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/ing_f/32/719347_2.png) [@Ing\_F](https://discourse.mcneel.com/u/Ing_F)\
**Post date:** [February 14, 2026, 9:44pm UTC](https://discourse.mcneel.com/t/colliding-inflating-bubble-and-anchored-cloth-rope/215932/1 "2026-02-14T21:44:46Z")

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Hi all,

I’m working on a hypothetical inflatable pavilion, held down by a tensile rope structure where the bubble’s inflation/expansion collides with the anchored rope/cloth making it tensile.

here are two reference images of something similar:

 ![Horticultural-Spa-and-Apothecary-Experience-by-Loop-pH_dezeen_468_1](https://global.discourse-cdn.com/mcneel/uploads/default/original/4X/7/b/4/7b4d751d52219178585d62d6533bb94764b93b08.jpeg)

 ![Inflatable Pods - Ant Farm](https://global.discourse-cdn.com/mcneel/uploads/default/original/4X/4/3/8/438860f122d34b053cb674345e2637071eba3f46.jpeg)

The stage I’m at is that I have succeeded in inflating a bubble and moving the cloth separately and with separate solvers. However, my problem comes when merging the two. the idea is that the movement of the cloth/rope is dependent on the inflation/expansion of the bubble. the bubble shape should deform/expand a little through the holes when colliding with the rope structure. I’m hoping that should i succeed with the cloth, I take the edges, converting to pipe so that it is a tensile rope, anchored down.

[inflate attempt.3dm](https://discourse.mcneel.com/uploads/short-url/9lhOAh60jbaXr9l3Mp7vke14bo.3dm) (62.5 KB)

[cloth and bubble mesh collide.gh](https://discourse.mcneel.com/uploads/short-url/r5mC5rZwckccGYzfWZIMUtjyVPO.gh) (38.9 KB)

any help or suggestions soon would be really appreciated!

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**Author:** ![Quan\_Li](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/quan_li/32/679256_2.png) [@Quan\_Li](https://discourse.mcneel.com/u/Quan_Li)\
**Post date:** [February 15, 2026, 4:03am UTC](https://discourse.mcneel.com/t/colliding-inflating-bubble-and-anchored-cloth-rope/215932/2 "2026-02-15T04:03:10Z")

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[Modeling Membrane Tensegrity Structure Based on Origami Pattern - Grasshopper - McNeel Forum](https://discourse.mcneel.com/t/modeling-membrane-tensegrity-structure-based-on-origami-pattern/150968/2)

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**Author:** ![martinsiegrist](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/martinsiegrist/32/498369_2.png) [@martinsiegrist](https://discourse.mcneel.com/u/martinsiegrist)\
**Post date:** [February 15, 2026, 12:04pm UTC](https://discourse.mcneel.com/t/colliding-inflating-bubble-and-anchored-cloth-rope/215932/3 "2026-02-15T12:04:31Z")

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In your current definition, the two meshes in the soft body collision are in two separate lists. This input needs to be flattened.

 ![image](https://global.discourse-cdn.com/mcneel/uploads/default/original/4X/4/0/4/4041c4afa86dd29d8a3e43ebbb7975f0f5ff5b49.png)

And for better data structure, I suggest using the Entwine component instead of merging everything into one data stream.

 ![image](https://global.discourse-cdn.com/mcneel/uploads/default/original/4X/9/4/f/94f2908aa2683fe5f9aca6d6af656ac83990880e.png)

[cloth and bubble mesh collide.gh](https://discourse.mcneel.com/uploads/short-url/aN600Vgvdq3Ob3FXXLcGb4sgg4Z.gh) (27.6 KB)

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<div class="post-metadata">

**Author:** ![Ing\_F](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/ing_f/32/719347_2.png) [@Ing\_F](https://discourse.mcneel.com/u/Ing_F)\
**Post date:** [February 20, 2026, 7:29pm UTC](https://discourse.mcneel.com/t/colliding-inflating-bubble-and-anchored-cloth-rope/215932/4 "2026-02-20T19:29:03Z")

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Hi @martinsiegrist

Thank you for this!

I have tried connecting the tree branches to the multipipe and it seems to have worked out. The points at which the pipe and the balloon collide seem to overlap. Is this because the collision if between the cloth mesh’s interior edge crv instead of the pipe?

 ![solver to mesh edges to multipipe](https://global.discourse-cdn.com/mcneel/uploads/default/original/4X/e/4/d/e4d98771031d42da84434a4add1486ed8ee74b3a.png)

 ![pipe and balloon collide](https://global.discourse-cdn.com/mcneel/uploads/default/original/4X/e/f/2/ef2615f97257678712b94c6883f06970d7e86b09.jpeg)

Is there any way to resolve it so that the pipe is tensile, in a way restricts the bubble allowing the bubble to expand a little bit beyond the pipe?

 ![Mesh Collide Inflation Diagram](https://global.discourse-cdn.com/mcneel/uploads/default/original/4X/f/b/f/fbf54d7ec5a385ebd8beeecb5dde1ff0cbb77d77.png)

[cloth and bubble mesh collide, with multipipe.gh](https://discourse.mcneel.com/uploads/short-url/dIKAuCEdzwtIBglhpAwXGr0DiRt.gh) (27.9 KB)

Many thanks!

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<div class="post-metadata">

**Author:** ![Ing\_F](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/ing_f/32/719347_2.png) [@Ing\_F](https://discourse.mcneel.com/u/Ing_F)\
**Post date:** [February 20, 2026, 7:30pm UTC](https://discourse.mcneel.com/t/colliding-inflating-bubble-and-anchored-cloth-rope/215932/5 "2026-02-20T19:30:39Z")

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Hi @Quan_Li

Had a look at this, but it isn’t what I’m going for at the moment.

Appreciate it though, thanks!

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<div class="post-metadata">

**Author:** ![martinsiegrist](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/martinsiegrist/32/498369_2.png) [@martinsiegrist](https://discourse.mcneel.com/u/martinsiegrist)\
**Post date:** [February 20, 2026, 7:39pm UTC](https://discourse.mcneel.com/t/colliding-inflating-bubble-and-anchored-cloth-rope/215932/6 "2026-02-20T19:39:17Z")

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Take a look at this example here. It’s not exactly what you want but it might help you get a little closer…

> [@Balloon restricted by strings](https://discourse.mcneel.com/t/balloon-restricted-by-strings/137953/11):
>
> Here’s an example which is quite close to my scan above: Note the base brep is a revolved section of the ballon which is split into 4 pieces and then joined again. It is split so the mesh later on has vertices exactly on the symmetry planes. Without vertices and edges along the symmetry plane, the collision would not work as nicely. I’ve used a rod goal for the strings. The solid point collision is set so both solid and points are affected by the collision. Input geometry and a res…