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I have a model of a deflated balloon. I want to know if I can use shrinkwarp or another method to enlarge it to an inflated state.

enter image description here

I don't want to permanently change the models, I want to make it so I can animate something like the balloon getting inflated, so something like shrinkwarp I which can use to customize the shift between the two states.

Leander
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screwfe3d
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    Why this is downvoted so much? Topic may be uncomfortable for some but actually the question is hard. – cgslav Jul 08 '18 at 10:47
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    @LukeD because it is irrelevant that it is a penis and the task is to erect it, the example and task could have been abstract. Imho NSFW content should be avoided here and clearly the rest of community thinks so too. – Jaroslav Jerryno Novotny Jul 08 '18 at 10:53
  • I'm sorry, i didnt mean to make anyone uncomfortable, and i didnt know where else to ask for help. If you can could you direct me to somewhere else i can get assistance. – screwfe3d Jul 08 '18 at 11:00
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    You can get assistance here, just be mindful of other people visiting, maybe they are using the site at work or are underage. The solution for changing one mesh into another with the same topology is using Shape Keys. You can also use them with armature deforming to get the best results. – Jaroslav Jerryno Novotny Jul 08 '18 at 11:03
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    @Jaroslav Would this be okay? I guess the answer would still be applicable, but the question wouldn't generate that many downvotes. – Leander Jul 08 '18 at 11:05
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    Thank you so much for changing it, and i'm srry about the nsfw, im still very new to blender and using forums – screwfe3d Jul 08 '18 at 11:07
  • @Leander not just ok, perfect! – Jaroslav Jerryno Novotny Jul 08 '18 at 11:12
  • @JaroslavJerrynoNovotny You didn't get the pun, didn't you? Also the edit from Leander seems not to be the same case. For the balloon you can use Cloth Simulation, for erection with foreskin stretching animation - it's impossible. So yeah, maybe some abstract way could be better but this one isn't similar (only semantically). – cgslav Jul 08 '18 at 13:58
  • @LukeD I did get the pun, a good one indeed:) – Jaroslav Jerryno Novotny Jul 08 '18 at 14:19
  • Great edit, responses and answer all around. Thanks for stepping up guys! – iKlsR Jul 08 '18 at 19:43

1 Answers1

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If you have 2 version of the same geometry created with sculpting for example, you can morph between them with a mesh Shape Key

Select the object you want to morph into, shift-select the base shape object (so it's last selected and active), add a Basis shape key (if not present) and finally choose Join as Shapes from menu:

enter image description here

This will create a linear morph animation if you animate the Shape key Value:

enter image description here

Easiest and fastest solution, not the best quality though.

To add more realism you can mix it with armature deform. For raising the deflated balloon a finger rig is suitable:

  • add Armature > Single bone, extrude the bone in edit mode, position the bones and make sure they are oriented so they rotate in their x-axis

  • bind the mesh to the armature

  • you can either make an animation of rotating the bones or create an extra control bone with disabled deforms, that will drive the others through a Transform constraint - the scale controls the rotation:

    enter image description here

  • this works like so:

    enter image description here

Now the Blend shape needs to be just the inflation and not any of the raising that the armature already does. Because Blend shapes are evaluated before the armature modifier you have to do the inflating with vector displace or do the following:

  • create a duplicate of the armature
  • animate/adjust the armature to the raised state
  • apply this state as the new armature's rest position: Pose > Apply > Apply Pose as Rest Pose
  • transfer the bone weights from the deflated mesh to the inflated one using Data Transfer modifier in topology mode (momentarily disable any modifiers on both meshes, generate layers and apply the modifier)

  • add armature deform modifier to the inflated mesh and animate it down (change the constraints to move it back down):

    enter image description here

  • now create the Blend shape of just the inflation:

    enter image description here

Optionally you can add a driver for the Blend shape Value and drive it with the Control bone's scale:

enter image description here

You can even add some math to the driver so the Blend shape is not linear and inflates the balloon more to the end of the rig movement. This depends on the application.

For more complicated armature deforms I can link here this:

Animating a punctured torus

Jaroslav Jerryno Novotny
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