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In the last homework project for my Blender class, I had to make a balloon bounce across a ceiling as a soft body driven by wind. I fiddled with the constraints but it always crumpled on impact with the ceiling. Adjusting the constraints so that it retained its shape resulted in it not reacting to the wind. Why is this and how do I prevent it?

Balloon goes up

Balloon Crumples

Balloon keeps on Crumpling

Duarte Farrajota Ramos
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    I'm not an expert on this, but is the soft body really the best/mandatory option? Can you use a rigid body instead? – Kyle Willey May 22 '13 at 20:52
  • Was required for the assignment in question. It likely isn't the best option but I'm curious if it's possible using this method. –  May 22 '13 at 20:53
  • Ah, then I won't be of terribly much help.

    Are you sure that the value you are changing on the soft body refers to rigidity as opposed to the "dampening", which I believe applies equally to all forces? (I've done more physics stuff in Maya, so I might be entirely in the wrong place here).

     – Kyle Willey May 22 '13 at 20:54
  • http://wiki.blender.org/index.php/Doc:2.6/Manual/Physics/Soft_Body

    "Soft Bodies work especially well if the objects have an even vertex distribution. You need enough vertices for good collisions. You change the deformation (the stiffness) if you add more vertices in a certain region (see the animation of Image 1b)."

    "Try and use a Lattice or a Curve Guide Soft Body instead of the object itself. This may be magnitudes faster."

    If you tried with a lattice or curve guide it may be easier to see where things go wrong, though I don't know if it would fix the issue.

     – Kyle Willey May 22 '13 at 20:57
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    A Blender class? Is this at school? – A Wild RolandiXor Has Appeared May 25 '13 at 23:07
  • It was at school, yes. –  May 26 '13 at 03:14

3 Answers3

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With Blender 2.66 or later, you can use a combination of rigid body physics and softbody on the same object. This should help you achieve the effect you want.

Also, increase the goal value and goal stiffness in softbody settings will help you retain the shape of a mesh.

Take a look at this sample scene

Mike Pan
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    Great to see you here Mike, lets hope we get some more professional gurus such as yourself. ;) – iKlsR May 22 '13 at 22:11
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You could also use the Bending and Push values in the Physics > Softbody > Softbody Edges panel.

Probably slower and unnecessary in this case, but I thought I would mention it.

Here is a nice video with examples of the settings.

EDIT:
in my experience also enabling "stiff quads" helps keep things in shape as well.

gandalf3
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  • when you posted this answer, was your reputation at 1? just curious as this is the first question. probably a duh moment hahaha – Harry McKenzie Aug 08 '23 at 05:43
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    @HarryMcKenzie oh gosh idk, I didn't join until a few months after the site went public, so probably not? but maybe? its crazy its been 10 years – gandalf3 Aug 10 '23 at 18:44
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There's an old and simple trick: put edges inside your balloon. Every additional edge acts like a strut, which helps to stiffen the balloon. Although balloons don't change their shape at all, excluding the knotted end.

Haunt_House
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