I would really appreciate some help here. I am trying to create a scene where I want the volumetrics to create sunrays coming through the trees. I cant seem to get it right, in that I can make things hazy, but I just cant seem to get the rays to show up. If anyone has an idea for a reference scene with the relevant settings so I can at least start playing in the right area, I would be happy as larry :)

Here is the kind of thing I am looking to reproduce... (sorry for the massive url).

http://images.google.com/imgres?imgurl=http://www.essentialindia.org/album/slides/Sunrays.jpg&imgrefurl=http://www.essentialindia.org/album/slides/Sunrays.html&usg=__9bzvwdHokw4c672cjipa8Mo6zAA=&h=600&w=789&sz=93&hl=en&start=22&tbnid=RBpm9zKzgT6QYM:&tbnh=109&tbnw=143&prev=/images%3Fq%3Dsunrays%2Btrees%26start%3D20%26gbv%3D2%26ndsp%3D20%26hl%3Den%26safe%3Doff%26sa%3DN

I am using Vue6 xStream.

Many thanks in advance,

Attached Link: http://www.renderosity.com/mod/gallery/index.php?image_id=1775848

Thats perfect, if you are willing to share it would be a great place for me to start playing. I want my scene to be more into the sun rather than an oblique, but it looks like your scene has what I am looking for as far as atmosphere and lighting goes.

I would also like to compliment you on the scene... its very good..

Thanks for replying.

Just wondering Rutra,.

I really like the rays - super realistic scene too, very nice - and they are produced because of light passing through dust and elements in the air, but the figure looks like she was pasted on top of all of it.

Is there a way that she an look like she's in the midst of the misty air, having to peer through the rays to see her?

Michael

I can't give you the scene file because it has several purchased items (trees and other plants) and I would be violating copyright. But I can give you the main pointers:

Light tab of atmosphere settings:

• Lighting model: I used GR but you can also use GI, if GR is too slow for you.
  - Atmosphere: I used spectral.
• Light balance: this is very important, it should be more towards sunlight than ambient because if you use too much ambient, the rays are less visible. I used 79%.
• Sky dome lighting gain: because the light balance is so high, the shadows will tend to get too unrealistically dark. So, you should compensate it with the sky dome lighting gain. I used 1.5.

Sky, Fog, Haze tab:

• Haze: it's important to have some to give some sense of depth. I used 25%.
• Fog: I used zero.
• Luminosity: I used only 1%. If you set it very high, the ambient becomes too bright and the rays are not so visible.

Sun:
default.

Rays:
I used a spot light with the same orientation as the sun to ensure lighting consistency (the easiest way to do this is to link both sun and spot light to the main camera and place them physically on top of each other). The spot light has a default configuration, with the exception that it's set to volumetric (quality of volumetrics at 3 to eliminate the grain) and it uses shadow map.

There has to be trees in front of the spot light, of course, this is what interrupts the volumetric cone and causes the rays to appear. The amount and placement of trees is just a matter of trial and error, there's no tricks that I know of. Just place a few trees, test render, move them, test render, move them again or delete some or add some, test render, move a few, etc, etc, until you get it right. If you are lucky, you'll get it right after a few minutes, if not this can take hours. It also depends on how perfectionist you are. :-)

Good luck!

Thank you Rutra! unfortunately the wife is banging my ears as we are off out for dinner, and with it being new years eve I wont get a chance to try until tomorrow... I cant wait...

Thanks again, very helpfull!!!!!

Quote - "... but the figure looks like she was pasted on top of all of it."

The figure may look that way because the eyes are not expecting to see a human flying above ground and because there's no clear reference that links her to the rest of the ambient (if a human is on the ground, the feet are touching the ground and there's a clear visual reference). In fact, the figure is scalled correctly in proportion to the trees and it's physically placed in mid air. But I know what you mean.

Quote - "Is there a way that she can look like she's in the midst of the misty air, having to peer through the rays to see her?"

Yes, I could place her in the middle of the rays. She would interrupt the volumetric cone and the light would seem to be passing around her. That could be a good trick to position her more obviously to the viewer, have to take a mental note on that for the next time. Thanks! :-)
The only point then, if I would do this, would be composition. I would have to add something on the left side of the image to balance the composition because then the right side would have a lot more "visual weight".

EDIT: Or maybe not, maybe the iluminated ground on the left would be enough to balance it. Would have to try it.

Rutra, thank you so much, it seems that the spotlight has done the trick. All the other settings I had played around with and was hoping or expecting the sun light to do the job, but its the spotlight that creates those very spectacular rays.

Its so simple I am kicking myself for not trying it before posting. On the up side I got a look at your work which I may otherwise would not have, so I won twice in the end.

Thanks again, and if its 2009 where you are, Happy New Year!!