Hello.

I have some spheres acting as vellum cushions under an animated collider (shoe).

They start off small and hidden and then animated rest / stiffness they explode out the side of the bottom of the shoe and interact with the floor.

How would I go about getting them to move back to their original small / hidden shape before they explode out?

Many thanks in advance!

(collider geo not attached)

I have not opened your .hip file but just sharing my two cents; You would probably want to animate the restlength on the contraints and simultaneously the thickness on the points (so that they won't collide and go crazy when the constraints pull them close together). To do that, you could either use a vellum rest blend inside a DOP network, or use a geometry wrangle / VOP to handle it all explicitly. You can set the inputs in the input tab of the wrangle/VOP. Point those to the appropriate fields; Geometry (the vellum points) and ConstraintGeometry (the constraints). At some point you can even turn point collisions off so you can make your balloons infinitely small. You can use the s@collisionignore attribute for that; https://www.sidefx.com/docs/houdini/vellum/vellumattributes.html [www.sidefx.com]

Hope this helps, cheers

Robbert
I have not opened your .hip file but just sharing my two cents; You would probably want to animate the restlength on the contraints and simultaneously the thickness on the points (so that they won't collide and go crazy when the constraints pull them close together). To do that, you could either use a vellum rest blend inside a DOP network, or use a geometry wrangle / VOP to handle it all explicitly. You can set the inputs in the input tab of the wrangle/VOP. Point those to the appropriate fields; Geometry (the vellum points) and ConstraintGeometry (the constraints). At some point you can even turn point collisions off so you can make your balloons infinitely small. You can use the s@collisionignore attribute for that; https://www.sidefx.com/docs/houdini/vellum/vellumattributes.html [www.sidefx.com]

Hope this helps, cheers

Don't think this answers the question at all, but thanks.

I'm just looking at how to restore original shape size of the sim, almost like a reverse of the animation caused by already animating the restlength, reverting back to original state whilst still being affected by vellum.

Cheers,

why not just key the restlength back down? :P

danvsmachine02

Robbert
I have not opened your .hip file but just sharing my two cents; You would probably want to animate the restlength on the contraints and simultaneously the thickness on the points (so that they won't collide and go crazy when the constraints pull them close together). To do that, you could either use a vellum rest blend inside a DOP network, or use a geometry wrangle / VOP to handle it all explicitly. You can set the inputs in the input tab of the wrangle/VOP. Point those to the appropriate fields; Geometry (the vellum points) and ConstraintGeometry (the constraints). At some point you can even turn point collisions off so you can make your balloons infinitely small. You can use the s@collisionignore attribute for that; https://www.sidefx.com/docs/houdini/vellum/vellumattributes.html [www.sidefx.com]

Hope this helps, cheers

Don't think this answers the question at all, but thanks.

I'm just looking at how to restore original shape size of the sim, almost like a reverse of the animation caused by already animating the restlength, reverting back to original state whilst still being affected by vellum.

Cheers,

I might totally misunderstand what you are trying to do then? If you want to return to the original size (which I understood as small/hidden) then animate the restlength and thickness back to the original states as mentioned before. If that does not solve the problem then I just don't understand what you are trying to do.

HM_2020
why not just key the restlength back down? :P

Hey,

that just deflates the balloons, but doesn't shrink them back to size.

Thanks

is this not what you want?

HM_2020
is this not what you want?

That's definitely closer than what I was getting in terms of getting back to the original size. Nice one thank you

Although there's some missing parameters when i open the scene, are you using some newer version of houdini?

I'm on 19.0.

Also they seem to squash more in your scene without a collider, which isn't needed.

I will try looking more into it, is that all that was done. animating the rest length down to 1 then zero?

Many thanks!

HM_2020
is this not what you want?

basically this is what i'm trying to do have a vellum sim for a sole from nothing to this and then back to nothing

yes, 19.5... and just play with the settings to squash less, I was just quickly playing with it to show you it works.