As much as I'de love to scour the archives to the answer to this question... :) How on earth do you get that nice volumetric sunlight bursting out of the clouds diffused by that huge tree with many branches and get the particles of dust caught in the light on it's way to your face? tah

Here are links to 3 tutorials on streaming lights/volumetric lights. Hope this is what you are looking for.

http://www.j.b.allen.btinternet.co.uk/voltutlights/voltutfrset.html

http://www.brycetech.com/

http://www.petersharpe.com/

Your best bet i to try "Volumetric world" setting. Unfortunately this very time consuming. I have yet to see even a render time estimate on simple scenes. Add a couple of volumetric clouds and probably the render times are a couple of years per picture :( Use volumetric lights? Unfortunately they work badly with volumetric objects. I just hope Corel would correct glaring rendering errors with volumetric objects, lights and metaballs.

Attached Link: http://www.unc.edu/~haraszti/volumetrictut.html

Volumetric lights arent truly too difficult, those first links above are the best to look at. But, using the "volumetric world" settings in sky lab are not really advisable, the rendering times are just way too long, since they turn your ENTIRE world volumetric, not just one light ray. Also, here is a link to a tutorial to add in volumetric effects in Photoshop after rendering, might help. Check out the guys gallery, some great examples of post-work volumetrics. Agent Smith

Love playin' with volumetric lights. Check out my render in the beginners gallery called "Rays". This took 7 hours to render and I have a big bad computer with 1500RAM..but there is a lot of trees too.