Shaft of light v3 - possible NWDA entry

FrankB · May 26, 2009, 09:35:50 AM

calico is right in that the areas where the sun hits the ground are strangely colors. I see very bright and very saturated green, and splotches of very bright and saturated red.
can you see that, too?

domdib · May 26, 2009, 09:42:23 AM

I think the saturation is partly the result of colour choice in the shaders, partly the result of the intensity of the ray, and partly the result of Photomatix processing. Obviously, any one of the three can be adjusted, and I think I will definitely tone down the red. However, I wonder whether this saturation is after all so unrealistic, as nature herself can surprise us in unusual lighting conditions, such as here when most of the rest of the scene is effectively monochrome.

rcallicotte · May 26, 2009, 10:05:43 AM

A couple of ways I know are good to do this -

Maybe the best one - use the selection tool to select the areas you don't want to change, select Invert Selection and then adjust the Levels slightly.

The way to do this with the burn tool would be to do this -

1. Add a new layer on top of the original.

2. Choose Overlay as the blending option.

3. Do all of your burning set at a low percentage but on top of this new layer.

A combination of both of these would probably work best.

Quote from: domdib on May 26, 2009, 08:57:11 AM
Thanks for the comment calico. Not sure which area you see as supersaturated - do you mean the bit where the ray of light hits the ground?. Also, your instructions re burning in the shadows are a bit too brief for my poor comprehension/image editing skill-set. Can you suggest an online resource that might spell it out a bit more? Thanks!

domdib · May 26, 2009, 10:13:19 AM

Thanks again calico. I will probably, as I mentioned in the last post, desaturate the red in the scene itself. That, by itself, might tone down the green, as being complementaries, the contrast will be reduced.

domdib · June 11, 2009, 05:51:09 PM

Here is the latest version. Desaturated the soil; added a heightfield erode and a displacement surface layer. Am beginning to run out of things to tweak. Any suggestions?

domdib · June 12, 2009, 04:44:48 AM

Come on guys, throw me a bone! Does no-one have any thoughts on how I could improve it?

Henry Blewer · June 12, 2009, 05:12:24 AM

Are you using ambient occlusion? Try making the surface strength 1.3. Also changing the fake internal scattering of the clouds may make them glow more; increase that by 0.2. The clouds edge sharpness might be too high. Lastly, add some tight grass objects. The object scales should probably be 3 greater than the smallest scale for the largest scale.

MacGyver · June 12, 2009, 05:25:23 AM

Quote from: njeneb on June 12, 2009, 05:12:24 AM
Are you using ambient occlusion? Try making the surface strength 1.3. Also changing the fake internal scattering of the clouds may make them glow more; increase that by 0.2. The clouds edge sharpness might be too high. Lastly, add some tight grass objects. The object scales should probably be 3 greater than the smallest scale for the largest scale.

I would say these are some nice tips for the start

I always wondered when I looked at your picture about how one perhaps could achieve a more defined ray but I had no idea... what lighting do you use, global illumination, ambient occlusion or none? I always noticed very different results changing among the 3 possibilities. Don't know if this helps...

Henry Blewer · June 12, 2009, 05:30:31 AM

I have the best luck increasing the atmospheres haze density. Sometimes it is necessary to increase the sun light strength. Crank the cloud samples up to 1. I have been using 128 for the atmosphere samples, it defaults at 16. Anything more than 128 really makes for longer renders.
I have only just started messing around with ambient occlusion. All the god rays in my pics use global illumination.

domdib · June 12, 2009, 05:45:25 AM

Thanks for your suggestions. My cloud samples are already at 266 (quality 2+) and atmo at 128, sun strength at 6 and haze density at 3.2, which are quite extreme. So there isn't much scope for change there. I can probably get a slightly more defined ray if I process this through Photomatix - this image is just a straight jpg at 0 exposure.
EDIT: I'm not too worried about the clouds and ray in general - more the terrain.

Using GI for the Environmental light, which is cranked up pretty high too (on surfaces only - mmm, maybe I'll try it in the atmosphere) EDIT: no, doesn't help the ray.

I'm not sure that adding grass objects is an option, as the nearest foreground is still quite some distance from the camera. I dismissed fake stones for the same reason - but maybe it's worth a shot.

Henry Blewer · June 12, 2009, 10:29:02 AM

Even from this distance to the hillsides, the grass objects will add texture. Especially if the smallest and largest scale sizes are exaggerated.

FrankB · June 12, 2009, 03:54:29 PM

Dominic, I have visitied this thread a couple times now, and I was trying to come up with some tips on how to improve the image further, and help with improving the beam and quality issues, but I could not think of much. Now I think I know why. Your entire scene is really really demanding for TG2. It's going to be very difficult to get out much more than this. One suggestion would be reducing the exposure much when you load the exr, and increase shadow highlights in post, but the real problem is the difficult scene itself.

If you still want to keep at it, I would try a different terrain, that allows the viewer to see much farther. The new terrain should also have much more smaller terrain features, to create the impression of big scale. A couple of known objects (besides the trees) will also help to understand the scale, by e.g. adding a house, a road, a car, whatever.
IF you are going to try a different terrain, my tip wold be to build it under a plain blue sky, so that you have much faster test renders, and can attend to terrain and vegetation distribution detail easier during the creation process.

Best regards,
Frank

Hetzen · June 12, 2009, 06:07:53 PM

I'd be tempted to crop into this, so that you have a diagonal from top left to bottom right, and not worry too much about the details in the shadows, infact the silhouettes would be more interesting. I think you could get this by cranking an exr in post.

Have you thought about shifting the terrain with a transform shader, so that the mountain peak get's the light? It would give you more focal area to concentrate and work on.

domdib · June 12, 2009, 06:54:18 PM

Frank - thanks for this very thoughtful response. A lot to chew on.

Hetzen - I guess I was focusing more on the details in the shadows because the NWDA contest is about realism, and I was trying to find ways to up the realism in the terrain - but as Frank points out, this might be a losing battle given the lighting conditions and POV.

Hetzen · June 12, 2009, 07:21:15 PM

I wouldn't give up on this at all. You can still fake this to make it believable. Instead of sunlight, make it moon lit. All you need do is change the sky colour, and get the terrain to move where you can put in some interesting, but focused accents. At the moment your light hitting the terrain isn't defining a shape. Reality is what the viewer wants to believe.

What you have done here, is worked on and demonstrated to all of us what the complications of working on low lit scenes in TG are so far. What ever you decide to do with this, I think will be an excellent lesson to all of us in atmosphere/extra lighting/GI/AO settings.