How would you go about creating a player driven inflatable balloon in Unity 3D?

Unity Engine
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1

I want to make a balloon inflate or deflate depending on player input. What would be your approach for doing this?

2

How about using transform.localScale to change the size of the balloon?

3

just recently tested with localscale also, good enough: check @53minutes

(just missing realistic random flying path when it deflates)