Absorption like Krakatoa for Smoke Volumes

[whodini]

Hey all, I'm curious if there is a way to render volumes such as billowy smoke with absorption . Here is a reference of absorption done in krakatoa http://assets.digitaltutors.com/dtv_/bison_courses/558/detailed_images/5.jpg

I've tried setting up a few lights and tweaking the billowy smoke material but I can't seem to get the right look as shown in the reference. Any advice would help.

Thanks!

Edited March 19, 2014 by rhussain

[Fabiano Berlim]

Access Denied

[rafaelfs]

Hey all, first post. I'm exploring houdini and I've previously used fumefx and krakatoa for smoke and fire simulation. I'm curious if there is a way to render volumes such as billowy smoke with absorption or some sort of subsurface scattering appearance. Here is a reference of absorption done in krakatoa http://assets.digita...ed_images/5.jpg

I've tried setting up a few lights and tweaking the billowy smoke material but I can't seem to get the right look as shown in the reference. Any advice would help.

Thanks!

I can't see your reference, but you can get volume scattering by setting the "volume limit", in your mantra ROP, to something higher than 0. It comes with a cost though...

Also would be ideal to use Micropolygon PBR.

Cheers

[whodini]

brilliant! volume limit does exactly what I want, it lets the light scatter through. Thanks! Also is there a way to have a specific color scatter through for example yellowish skin color for the outer part of the smoke and red tone for the inner smoke. I'm guessing this is a shader manipulation thing. Or how can I ramp the smoke color based on density (less dense = yellow, very dense = red) I've does this kind of thing with particles color attribute using a vopsop.

Edited November 28, 2012 by rhussain

[Annon]

Well if you use the pyro shader you can have a ramp style thing for free.

Initially it looks at the heat field, but you can use whatever field you want and change the ramp colour to whatever you want.

[whodini]

thanks ChristianW, I didn't know that pyro shader was available. It's awesome and a great shader to study.

[nord3d]

By the way, there is the reference image from the first post:

Edited November 30, 2012 by nord3d

[Alexander Saraev]

Sorry for bumping the thread up, but the question seems really interesting. And we have reference now

So is that doable with Mantra? I mean it's probably most certainly doable, but well, maybe someone would like to shed some light on the topic, Mantra-wise. I believe there are clues which could be found in this paper below, but picking them ain't too easy for an average artist like myself:

http://magnuswrennin...Effects2010.pdf

Thanks guys.

Edited August 8, 2013 by Alexander Saraev

[Hazoc]

Here's a link and a shared hip file that might give some insight how to do this stuff in houdini:

http://mattebb.com/weblog/rendering-clouds-with-the-mie-phase-function/

[Jordan Walsh]

Old thread, but i was just playing around with this and got a similar look going

 

 

volumeAbsorption.hip