Filling a room with dust in the air

Scavenger

Presently, if i wish to show a room full of dust or mist etc, I may use a plane in front of a camera (which I think is how atmospheric cameras work) and like use a "god ray" or such hooked to a spotlight to simulate the light reflecting off the dust.

I'm wondering in a Physics based  renderer like iray or lux, is it possible to just fill a room with "dust" and have the light naturally create beams as it would do? or is faking it still the best way to go?

mjc1016

All 3 renderers are capable of doing that, without faking it, but setting it up is a bit of a pain in the posteriror.  Actually, in Studio, Volumetrics are easier to control in 3Delight than Iray...(they may render faster in Iray).  Luxrender is a bit easier than Iray to setup.

The volume shader in 3DL is particularly slow...but not too difficult to actually set up.

The key thing for all three is to start with something that will define the volume...usually a cube.  Most of the time the camera needs to be outside that cube.  Then apply the shader/material and tweak the heck out of the settings.  'Dust' is one of the harder things to do, because it is subtle.  Another thing, for 3DL having lights that accept categories is essential...

Mousso

Its hard in iray (and lux), but not impossible. Here is a tutorial thats good for a start http://sickleyield.deviantart.com/journal/Tutorial-Creating-Dust-And-Atmosphere-in-Iray-522291773

Then play around with SSS and Scattering Measurement Distance. If you want very subtle haze turn down SSS to 0,0010 and SMD to around 300. It worked pretty well for me in an outdoor scene.

Scavenger

Thanks! Now I have a starting place to learn out things, and some terms to use in googling!

Oso3D

If you are going for a haze that doesn't have godrays and similar, I highly recommend faking it and seeing if you can find some sort of depth render. Iray has a distance canvass I've never figured out how to use effectively.

In 3DL there's AoA Atmospheric camera, which will set up various cool camera-based fog/haze stuff that CAN do godrays. It ALSO has a kick-a* depth camera, which I've actually used for Iray renders (as a way to mask based on distance).

 

Volumetrics are HIDEOUSLY slow for renders and it's almost always better to fake it if you can. That said, it can be satisfying to play with by itself.

mjc1016

A couple of tips to speed up volumetrics...in 3DL, at least.

1. Don't use any GI type lights for the volumetrics.

2. Use occlusion overrides on transmapped items...like hair.

For Luxrender and Iray.

1.  Limit the volume to just what is needed.