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I'm trying to simulate an inflatable mesh by applying a force field to a cloth. As air pressure always acts perpendicular to a surface it might be a close enough approximation when pushing all vertices along their normal vector with equal force.

Blender's shrink/fatten-tool (Alt-S) won't do the trick as it doesn't create the neccessary creases in the mesh when there is excessive material available. Think of a cloth laying on a sphere, where the excessive material gets pushed out and creates these folds and wrinkles. It's kind of similar to the case I'm trying to simulate, but instead of gravity pulling the cloth down on the sphere, thus having little force acting on the horizontal parts of the sphere, the air pressure pushes equally on every surface.

Is there a way to simulate a force field this? I think the weight of the mesh and the air are negligible in my case.

Edit: Example image added. Inflatable Letter S

YPOC
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  • Why doesn't cloth simulation work for you? (Properties editor > Modifiers or Physics tab > Cloth) Another way is sculpting wrinkles (if not for animation) – Mr Zak Aug 07 '17 at 14:40
  • I think cloth simulation is the right way to go because you can easily control stretching of fabric, which is essential for creating wrinkles. But I haven't found a way to simulate any kind of omni-directional force (i.e. pressure). And yes, I'd like to use it for animation. – YPOC Aug 07 '17 at 14:55
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    If the object is convex enough (i.e. no blind spots like sleeves) a central force field might do the trick. Of course this is not an exactly uniform force, but it's something (I've done something similar in the past: https://www.instagram.com/p/BTOP4XCATO6/) – Nicola Sap Aug 07 '17 at 15:11
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    related: https://blender.stackexchange.com/questions/81193/wind-pressure-inside-a-volume/81458#81458 –  Aug 07 '17 at 15:49
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    Use Soft Body rather than Cloth Sim - it's much more controllable - as in the answer linked by cegaton. – Rich Sedman Aug 07 '17 at 23:10
  • It depends on what else you want to do, but you could always create sewing lines to duplicate vertices scaled along normals, which will exert force along those verts normals. Pin them (that's where it matters what you want to do). Probably best to use it on a non-rendering object then use a surface deform to copy to a rendering object, as sewing lines will screw up smooth shaded normals. Simple to try, at least. – Nathan Jul 03 '18 at 03:44
  • Are you using an actual wind force field or are you using modifiers? The way I see it you should create a wind that blows into your 'balloon' so that it can blow up. Just Like a normal balloon! – Fateh A. Apr 12 '20 at 23:10

2 Answers2

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Why aren't you just using pressure in cloth sim? Make a flat S, solidify it but keep it flat and blow it up with cloth sim. then you get the best creases.

enter image description here

Roel Deden
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You could try the modeling cloth addon. It has an inflate option and I've seen a lot of images of people making inflated objects with creases like that. https://www.youtube.com/watch?v=yHGz7nEI23E https://github.com/the3dadvantage/Modeling-Cloth

Rich Colburn
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