I'm quite new in the blender world. I'm animating a balloon that has three fix points when it inflates/deflates and I want it to fly away at a certain point of the animation following the physics I already added, like the wind. I've seen that i can move the points and insert keyframes in edit mode but I want it to be realistic and just fly away. Is there a way to remove or deselect a vertex group at some point?




  • $\begingroup$ hello, could you please show some illustrations or picture of what you want to do? $\endgroup$ – moonboots Jul 1 '20 at 12:38
  • $\begingroup$ yes of course, tell me if you need something more to understand $\endgroup$ – Valentina Gentili Jul 1 '20 at 12:53
  • $\begingroup$ do you mean this vertex group is used to pin the mesh during cloth simulation? then you don't want it to be taken account of? $\endgroup$ – moonboots Jul 1 '20 at 13:42
  • $\begingroup$ yes exactly is what i'm trying to do $\endgroup$ – Valentina Gentili Jul 1 '20 at 13:53
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    $\begingroup$ Hi. Please use the built-in uploader when adding images. See: meta.stackexchange.com/questions/75491/… . Thanks. $\endgroup$ – Ray Mairlot Jul 1 '20 at 14:41

So it looks impossible to directly animate the Cloth Pinning. The question has been asked here and here, but I'm not sure to understand everyhting.

I've found an other solution, a rather simple one, with the Vertex Weight Mix modifier, but there must be others:

  • Create your object, give it 2 vertex groups, one for the pinning, the second one must be empty. Give it the Cloth physics.

enter image description here

  • Create a Force Field > Force next to your object. Animate it: give it Strength of 0 until frame 49 for example, keyframe it at frame 49, at frame 50 give it a Strength of 30.

enter image description here

  • Give your object a Vertex Weight Mix modifier, put it above the Cloth in the modifiers stack. Choose Vertex Group A > the pinning group, Vertex Group B > the empty group, Mix Set > VGroup A or B. Keyframe the Default Weight A and Default Weight B values: A will be 0 from frame 1 to 49, then 1 at frame 50, B will be 1 from frame 1 to 49, then 0 at frame 50.

enter image description here

  • It seems to work as planned, from frame 1 to 49, the object collapse with the pinning hanging it, at frame 50 it is blown away by the force field.

enter image description here


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