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chazfest

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Hi,

I've started playing with Houdini's new cloud FX tools and am wondering if somebody could enlighten me as to how I add an element of animation to my cloud?

At present, it sits completely static. It looks ace n all ^_^ but there's no animation (ie slow evaporation and reformation of the cloud). I've attached a project file to illustrate this (Cloud Static)

I also tried to parent the clouds transform to a null object in another project, but this just resulted in a really erratic reshaping of the cloud every few frames. Almost as if it was recalculating a new seed every few frames. I've attached this project file also (Cloud Erratic).

If anyone could shed any light on this for me, I'd be eternally grateful :)

Huge thanks in advance

Cloud Erratic.hipnc

Cloud Static.hipnc

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Check out the attached file.. it might help (there's stickies with info).

Adam, that's ace! Thanks for taking the time to show me :) I'll have a play and will no doubt have more questions soon.

I'd really like to reproduce a much smaller scale version of the cloud featured on the Guiness Advert for a personal project I've got in mind:

http://youtu.be/URxLYupra5s

Be warned, I'm likely to have many more questions :)

Thanks again

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Check out the attached file.. it might help (there's stickies with info).

Hi Adam,

Thanks again for this. I've played around with it and am still struggling. It seems that the noise animation causes the cloud to flicker erratically (I've attached an export to show this).

I was expecting the cloud FX to have a similar functionality to the smoke solvers, where I'm able to increase/decrease the dissipation rate to affect the speed at which the smoke rises, disappears, separates etc.

Is there any way I can add this kind of functionality to the cloud system?

Thanks again

Cloud Sketchy.mov

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It looks like you're transforming the object then creating the cloud stuff with it. Reverse this.. create your cloud setup and then transform it.

The cloud rig doesn't have any simulation components (good thing as you don't have to sim anything for quick results). Sounds like you'd like to sim your clouds; in this case have a look at the shelf Pyro FX->Billowy Smoke. This will create a DOP setup with things like speed/dissipation/cooling rate/buoyancy that you can play with.

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I'd really like to reproduce a much smaller scale version of the cloud featured on the Guiness Advert for a personal project I've got in mind:

Myself and another guy, Christian made the cloud system for the Guinness Ad. Annoyingly it as about 3 months before the launch of Houdini 12.5 so we have to build our system from scratch. It is based on the same kind of stuff though extracted from the Tessendorf papers.

I haven't yet had a chance to check out Houdini's new cloud fx toolset. It does look very promising, and is at the very least a good starting point to build upon and customize. It's cool that it uses VDB grids...

We bolted on a lot of simulated wisp elements to help bring our cloud to life.

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Myself and another guy, Christian made the cloud system for the Guinness Ad. Annoyingly it as about 3 months before the launch of Houdini 12.5 so we have to build our system from scratch. It is based on the same kind of stuff though extracted from the Tessendorf papers.

I haven't yet had a chance to check out Houdini's new cloud fx toolset. It does look very promising, and is at the very least a good starting point to build upon and customize. It's cool that it uses VDB grids...

We bolted on a lot of simulated wisp elements to help bring our cloud to life.

Wow, that's epic Tom! I love your work, it's really inspired me (evidently!). Just checked out your site and you've worked on some amazing projects. Thanks for the feedback, you're the perfect guy to pitch in with advice on this one, seeing as it's your own work that I'm aspiring to :)

The new CloudFX tools are great at first glance, though I'm struggling to get any kind of realistic, natural movement in them. I just want one very small, lonesome cloud, with a soft, slow dissipation. It surprises me that the CloudFX tools aren't set up to react to heat/cooling etc, they're just static, and seem to rely on you faking the evaporation/formation process by animating noise. I think I might try to create the cloud with a smoke solver instead. My knowledge of Houdini isn't great at this moment in time, and this is kind of an adventurous (perhaps overly ambitious) R&D project to learn more about Houdini. Here's hoping.

If you've any tips on where I could start, I'd be hugely grateful.

Massive congrats on your work either way, it really is amazing :)

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  • 2 months later...

I believe most of the new houdini cloud tools are at least inspired by, if not based on the work that Brett Miller did on clouds at DreamWorks:

http://www.museth.org/Ken/Publications_files/Miller-etal_SIG12.pdf

I think most of the shapes are modeled and then some simulated and some procedurally animated details are added.

Cheers,

koen

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Hey Charles,

The Guinness stuff me and Tom did is quite similar I believe to the new Houdini Clouds, but it's missing some of the extra stuff we put in there.

Basically you can't think of it as dynamic, it's volume manipulation using noise displacement. So you're not going to get "evaporation". You could add that in using a distance falloff etc to multiply the density if you like. As Tom mentioned, we did extra sims that were clustered on the main body of the cloud to add a bit of realism and to get evaporating parts.

As for animation, this is difficult, it's stamping values to pointclouds, manipulating the points then splatting back to volumes. Not difficult or ground breaking in itself, but can cause issues you have to work around.

You'll be better off reading some of the pdf's that are around about volume manipulation and learning what is going on, then you can either bodge it together in the existing cloud setup or make your own.

Good Luck

Christian

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