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dpap

how can I inflate cloth ?

How can I inflate a cloth object (a tube)?

I found no inner pressure attribute on the cloth object.

And also can wires interact with cloth?

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multi solver with cloth and sop solver, where inside the sopsolver you put a peak sop to push the geometry,?

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Thank you for your answer Pelos.

It works theoretically but after some frames things get really ugly. So practically it does not work I am afraid.

post-9497-0-76597900-1418896019_thumb.jp

inflate.hip

Edited by dpap

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Instead of setting a new P outside of the solver, it should be much nicer to set a targetv or targetP for the solver and let it do it's thing.

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Here's an example. Even though the stretch stiffness is quite low, it starts to fight back at some point.

 

attachicon.gifinflate.jpg

Hi eetu, thanks for the example, can you please explain "attribcreate_targetV' in sopsolver , why the calss is set to vertex not point? what is the different in DOP 

Thanks

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If you look at the geometry data in DOPs (with a spreadsheet or a detail view pane) you can see that the targetv and targetP normally created by the solver are vertex attributes, not point attributes. We want to override those values, so we need to write to vertex attributes.

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I had a really hard time doing some inflating cloth recently. I was trying to remake some old footage from the 60's of Project Echo [a large balloon made of very thin silvery material inflating in space]. What I ended up doing was making a rough animated version in SOPs, then using that as target geometry in DOPs, with some forces and so on.

 

The main problem I had was that being cloth, it can't really appear to stretch very much, else it would be more like bubblegum or something. So right from the beginning it has to appear that all the geometry is there, creased and folded up which of course isn't really feasible.

 

I'd be interested to hear your progress with your project.

 

This was my end result -

 

And this is a different treatment of the end of the shot...

Edited by j00ey
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Mmmh. The inflatee file doesn't seem to work anymore in H15. The sphere doesn't inflate at all. Anybody an idea?

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Anybody? I still don't get how to apply a force, like an inflate force, to the simulation on a per point basis. Could somebody update the .hip so that it works again?

Thanks in advance!

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For some reason seems like the targetP attribute needs to be a point attribute these days. (Even though the documentation says point or vertex).

 

Change AutoDopNetwork->sopsolver->attribcreate_targetV->Class from vertex  to point and it starts inflating again. Looks like the stiffnesses have changed in the solvers, so re-tweak.

Edited by eetu
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Thanks eetu,

This creates an inflation as expected. Do you have an idea how we could keep the same volume as on first frame? (Inflating or deflating along the sim).

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Hi,

The inflatee.hip file do inflate if we change vertex to point but the balloon is going up in the air... !

What's happening exactly ?

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Hi everyone, I figured out a nice way to suck air out of a piece of cloth, doing the opposite would likely inflate it. I simply advect the point along the gradient of the sdf. If you subtract the volumes of your collision objects from the volume of your cloth object the points will "collide" as in they won't advect into the collision objects. Further, you can calculate the length of the advection and if below a threshold you can tell it not to advect at all, this would avoid wiggle. 

Here's the example of my shrink wrap inspired by more and more, it's not on a cloth sim yet but it works in sops! It's a sphere shrink wrapping around several collision spheres within it.

Let me know if you have any questions! I've been meaning to do this process on a cloth object, if there's interest I'll make it a priority and share something soon!

 

 

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Doesn't seem to work in H16. Data in the DOPs seems to be a bit different. Any idea how to make it work?

Edit. Aaa it works after I changed the cloth object to newer one. Settings need some re-tweaking though.

Edited by Terisan

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Did you get this to work? Im really struggling with this. Im not really one to ask for a scene file but it would really help.

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2 hours ago, lemmingsammy said:

Did you get this to work? Im really struggling with this. Im not really one to ask for a scene file but it would really help.

Not sure what the old settings were relative to what these are now, but all I did was swap out the cloth object for the new one, put the stretch stiffness waaaay down, added some 'Target Strength' in the 'Deformation' tab (so targetP does something), and change the class on the attribute create in the sop solver from vertex to point.

inflatee_H16.hip

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