United3dArtists Archive

yup I know its a bit early (or is that late?) for Halloween, but I always wanted to do this and the mood struck. I really wanted some light rays going through the fog but such was not meant to be I guess, tried, tried and tried but volumetrics are a b****! Any suggestions with the image?

tS 5.1 sp2

Rob

Volumetrics depend a lot on camera angle- they are less apparent when the light is aiming straight at the camera, and become more visible the closer you get to 90 degrees from the direction the lights are facing. This assumes you are using a 'directional' type like a spotlight/area/projector etc.

Use 'Advanced Volumetrics' rather than 'Simple', they're faster and have more options.

I'm a little rusty on tS5.x, but try increasing the 'medium density'. This is the apparent 'thickness' of the fog.
Turn off 'medium shadows' to increase calculation speed. You can switch it back on if you wish for the final beauty render.
Turn off/ zero out any 'attenuation'
Under the 'Model', click and hold and choose either 'Greenstein, Mie Murky or Mie Hazy'
If the fog is too 'smooth', use a density shader (or adjust min and max LOD levels) to introduce noise. Will increase render times, so adjust this last.

For quick previews, use the Post Process Editor. This will render a small preview of the currently selected view- usually faster than waiting on full size renders.
Clicking inside the preview render window forces a re-draw, hitting ESC key cancels preview render.
To open it, right click on either the Glows and Lens Flare, Depth of Field, or Tone Mapping icons in the rendering options toolbar.

Try to change only one parameter at a time.

Patience is rewarded when working with volumetrics.

For a nifty rollover explanation/examples page, open this link in IE: http://www.stansight.com/3Dvolumetrics.html"
It covers just the Simple Vols, but is still helpful.

Save me the pumpkin seeds!

I think, not sure, that life size scenes do better with volumetrics. That is, set the world and object units to to realistic ones. Don't make an 8 foot tall wall as 8 units high when the units are miles or points or meters.

Another way to speed up test renders is to use draft antialiasing. In TS 5 this might make the render smaller than normal. In model side TS 7.6 it is normal size but low res.

Spacekdet & Finis,

Thank you both for your tips.

The image is using advanced Vol. I think density was like 12. I didnt use simple vol. because I didn't want to use a spotlight or projector, so I had to go advanced. For me the manual reads like a science manual under the ad. vol. section, hard for me to understand exactly what they are trying to say. I went isotropic w/turbulent for effect because some other options was washing out the scene even tho it didnt earlier on, I just got tired of going back and forth for 2-3 days. I forgot all about the using the post process editor view, I was using 'render portion of screen' a lot which helped, especially since everything in the scene is actually geometry and not alpha maps, for example.
Quite the coincidence that you give that link because I found that, I googled volumetric tutorials, didn't find anything really for tS adv. vol. but I did read the one you gave. I was trying to find something thorough maybe to even give tips on getting rays through the fog, but nada.
Thanks again for the tips.

kind regards
Rob