5 replies to this topic

[anupamd]

Guys, How would you guys set up smoke trails / streamers / shooters like this image WITHOUT doing a pyro solve?

I know we can do it as a pyro sim, but that requires simming and Im wondering if there is a simpler technique using particles and volume/masks.
Has anyone tried implimenting overburn technique in houdini?

https://vimeo.com/5429867

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[fxrod]

You can download a toolshelf from Side FX that has a contrails tool. These are covered in this series the Old School Blog.

http://www.sidefx.co...=559&Itemid=216

Should give you a good start!

[nomad]

Also, you can use sprites with a procedural VOP shader.

Once upon the time this technique was described in the 3Dbuzz tornado tutorial. (http://forums.odforc...d-buzz-tornado/)
After it was replicated many times, with different improvements.

.. it is an old technique, although it is very fast.

[anupamd]

Guys, I'd like to revisit this topic. I haven't found much info on using a procedural vop shader on sprites. Does that imply that you can basically render a sphere of noisey volume instanced to each sprite, with perhaps a flownoise that's stretched based on particle velocity? Does anyone have a sample hip with this working?

the other approach is to use a purely fluid based system which can work if you play around with particles, streaking them, adding some viscosity then using them as a fluid source but that option seems to soak up a LOT of sim time especially for shooters that extend out very far.

Basically end of the day Im looking to replicate the overturn technique.
https://vimeo.com/5429867

Anyone have any pointers?
Thanks,
- Anupam

nomad, on 01 June 2012 - 11:33 PM, said:

Also, you can use sprites with a procedural VOP shader.

Once upon the time this technique was described in the 3Dbuzz tornado tutorial. (http://forums.odforc...d-buzz-tornado/)
After it was replicated many times, with different improvements.

.. it is an old technique, although it is very fast.

[Ratman]

The way I've done this is by generating a few noisy volume spheres, either by sim or using volume vops to create a few random noisy volume objects.

Then I generate a particle system for the trail, then you want to use a delayed read object to load in the volume objects and apply them to the points.

The tricky stuff comes from when you want to use per point attributes and having each particle load a different volume bgeo.

-R

[efx]

Also you can use cvex volume procedural + instance.
I tested with H11 long time ago but this can be really similar with that Vimeo.
With this way, you need to use instance but don't need any volume cache because cvex shader can generate spherical volume + noise & displacement.
Also you can override with point attributes.

Problem is rendering time. I hope H12 can render much faster.

Check this post if you have not seen yet

http://forums.odforc...ed/page__st__24

Also you should check Putoparri's hip.

Cheers