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I've seen abstract animations around the internet, in which bubbles grow in size within a closed area and get squished against each other and the walls in a realistic way.

At 11 and 15 seconds there are similar examples of what I'm trying to achieve.

Trying to get familiar with Soft Bodies, I decided to try to reproduce this as a little exercise, however, I cannot seem to keyframe the Scale on a soft body: when I try to keyframe a scale on the objects it doesn't do anything.

It doesn't matter whether they fall or not during the animation (as long as they stay within the box), I was trying to get them to inflate and get squished with the other objects in the scene.

Here's the file:

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Unless you're using the soft body 'goal', changes to the original mesh will not affect the soft body simulation. Many of the other potentially useful parameters (such as Edge Length) are 'locked in' at the start of the simulation and changes similarly do not affect the simulation.

However, one way of achieving the desired effect is to use the Self Collision settings to exert a force within each 'bubble' to push it outwards, causing it to expand.

To achieve this, enable Self Collision and set the Ball Size to a suitably high value. This will simulate a collision ball around each vertex of the specified size, pushing each other vertex away. Set the Stiffness to a low value - this is the 'force' that each vertex is pushed away from its close neighbors. Reduce the Edge Pull to remove any force opposing the Self Collision 'push' and increase the Bending spring if necessary to prevent the bubble from collapsing. You should now find that each bubble expands to fit the available space.

Don't forget to add Collision to each bubble to prevent it from intersecting with the other bubbles and also set the Error Limit to a small value to improve the simulation.

settings

This can produce the following result :

result

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  • $\begingroup$ Great description, thank you! Although, managing 10+ balls at once can be a pain. Is there way to manage the soft body settings for a bunch of selected balls all at once? I have the to all plugin installed, but it does not include Physics settings. $\endgroup$ – wout Sep 24 '18 at 17:56
  • $\begingroup$ @wout You're welcome. If you have them all selected then you should be able to adjust the setting on one of them and right-click the setting and select 'Copy to Selected' to automatically copy that setting to the other selected objects. This doesn't need any add-ons and is standard functionality. I've tested this on the Length setting (in SB Edges) and this does seem to work fine for SB settings. $\endgroup$ – Rich Sedman Sep 25 '18 at 22:37

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