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Rubber/stretchy surface


meldrew

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Hello Odforce!

 

As this is my first post, please allow me to introduce myself.

 

My name is Tim & although I'm quite new to Houdini, I have almost 10 years of experience with C4D and other 3D packages.

 

I've spent around 4 weeks experimenting with houdini, and love it. Hopefully in time I will learn enough to be of use to other users on this forum! :)

 

 

So, my question!

 

I am attempting to achieve the effect shown in the attached image, using an animated model. The idea is to have the character really stretch a surface which is surrounding them.

 

I have experimented with the shrinkwrap tool, however I really want to get something that conforms to the body a little more, almost like it has been vacuum packed.

 

 

Now, of course I assume this can be done with the cloth solvers, however my experience with them is not great & I assume that the sim time is pretty heavy.

 

Is there perhaps a clever technique to do this within SOPs? If not, what would be the best way to approach this, from the very experienced minds here on odforce!? ;)

 

Thanks!

 

 

post-14317-0-37018400-1439645588_thumb.j

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Cloth attached to body is the easiest - check the attached - essentially you create the cloth by converting a 'peaked' 'shrinked wrapped' version of the original geo to vdb then back to polys- this is then shrunk back onto the original geo as cloth.

 

It's rough-as but might help to start.

 

Edit: PigRapped version added.

Shrinkwrap.hipnc

post-8321-0-90055600-1439697768_thumb.pn

WrappedCloth2.hip

post-8321-0-88055900-1439707748_thumb.pn

Edited by tar
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Cloth attached to body is the easiest - check the attached - essentially you create the cloth by converting a 'peaked' 'shrinked wrapped' version of the original geo to vdb then back to polys- this is then shrunk back onto the original geo as cloth.

 

It's rough-as but might help to start.

 

Edit: PigRapped version added.

 

Hi Marty,

 

Wow, thanks so much for these scenes... The second approach (clothed pig) is essentially what I was going for.

 

I've learned a lot from your setups, however I'm still struggling to translate the technique onto my animated mesh.

 

I've got it working on a 'mocap biped' in zombie mode & it works a treat, however when I try to apply it to the mesh I have to work with the technique breaks down, as the point-count of my mesh is changing at every frame.

 

(essentially it is a meshed fluid simulation, and there is no way I can convert it to a mesh with non-changing pointcount.)

 

Unfortunately I can't share my source mesh, however if you were to skin a changing num of particles filling a volume with 'particlefluidsurface' you would essentially get what I have.

 

Any ideas how I could adapt either one of the systems you have kindly shared?

Edited by meldrew
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(essentially it is a meshed fluid simulation, and there is no way I can convert it to a mesh with non-changing pointcount.)

 

 

Here's a way - you can 'average' the changing point count by wrapping a non-changing sphere over the fluid, using a RaySOp. Then you can pin you cloth to it.

 

Concept proof attached. Hope it helps!

post-8321-0-26721200-1439841914_thumb.pn

FLIPPy_ClothPin.hip

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Here's a way - you can 'average' the changing point count by wrapping a non-changing sphere over the fluid, using a RaySOp. Then you can pin you cloth to it.

 

Concept proof attached. Hope it helps!

 

 

Again, thanks Marty!

 

This setup is slightly out of my comfort zone, so might take me a while to run through and understand everything!  :)

 

One thing I'd like to ask though - And it's pretty noob:

 

In the 'liquid import' and 'liquid interior import' networks (where I can see the normalisation is happening) I'm getting an error in the DOP import nodes stating

 

'no DOP object names specified'

 

Is this something to do with the 'liquidsim' network being in playback mode? If so, how do I change that?

 

 

Thanks again, really appreciate you taking the time to help out!  :D

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Here's a way - you can 'average' the changing point count by wrapping a non-changing sphere over the fluid, using a RaySOp. Then you can pin you cloth to it.

 

Concept proof attached. Hope it help

 

Ok, so I have 1 final question on this, then I should have a nice solution wrapped that I may be able to share on here in coming days! :)

 

If I have my particle/point changing mesh as a deforming collision object, is it possible to use the shrinkwrapped/wrapped_cloth techniques on it? Or is that still a no-no because it's using the point selection as a constraint?

 

What I'd love to be able to do is:

 

-ROP out a geo sequence of my mesh

 

-Bring it back in > At frame 1 create shrinkwrapped cloth geo

 

- Use the geo sequence as deforming collision geo

 

-Run through 'wrappedcloth' system, so the shrinkwrapped cloth conforms/solves to the mesh at every frame.

 

I've tried every logical way I can think of to achieve this, no joy as of yet.

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A bit busy currently so I'll leave this part up to you, or others, as a challenge.  

 

Houdini is a like a set of tools for solving problems and I think this is great one to solve!  

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