Inflate or Deflate a mesh?

Hi All,

I have a mesh in the shape of the letter S, shown in image. I would like to make the mesh look inflated and or deflated at different times. Does anyone know how to achieve this in Blender? In 3dsMax I would probably just use melt but I can not figure out how to do this in Blender. A balloon expansion and or melting effect would be ideal.


USe shapekeys to change its shape.

To inflate you could try Alt+S
To deflate you could try a Laplachian Smooth modifier with a very high Factor and ‘Preserve Volume’ disabled. You can then apply this as a shapekey which you can then animate.

The actual effect may not be exactly what you want but worth trying

Try out alt+s and see if it is what you want. Actually alt+s just scale along the normals

You could add a cloth modifier with a plane as a collision object. You would have to arrange these so that gravity has the effect you want. Then go to the frame that has a suitable deflation and in the modifier panel apply as shape key.

Thanks all for the tips.

@Richard: How did you get those seams on the far right version of the S? That is very close to what I am looking for.

@AlanK: The cloth tip works great for deflate. I was playing around with soft body and getting nowhere.

i was playing with some script and i got a strange inflated model

let me know if you want to try it
but it is still a wip

happy bl

I’ll check it out once you post it Ricky!

I think it was quick and dirty crap topology.
Added a text object for the S, extruded to give some depth, converted to a mesh, then added a remesh modifier to give a more even mesh to deform. I think it was set to smooth so the edges were a little crinkled. Applied the remesh modifier then added a subsurf before using Alt+S to inflate

@ Atom i PM you a file link
cause the script was too long to add here!

to see it works
select first menu item X
then click on bottom button call custom then it will inflate the selected object somehow!

let me know if it works!

happy bl

Thanks for all the help, I have what I need to make my letter S.


Looks good! :slight_smile: