This is a set of four images that explain in more details the request for a change in Carrara that I was talking about in an earlier thread. The first image is of the scene rendered using the realistic sky setting and using skylight. I liked the look of the sky but I didn't like the result when rendering the skylight. It's too blue and cold. To manage this, I rendered the sky alone (image 2) and saved it as a separate image. Then I put a bi-gradient into the background (image 3 shows this just for fun) which had a warmer color at the top and faded to grey at the bottom. When the sky image is placed in the backdrop with the same bi-gradient in the background, I get a warmer light that's fuller and more under my control. The previous thread discussed managing this issue by using a sky dome but this won't work when I want to use the realistic skies or the starbright plug-in during animations or to change the POV easily. What I want is to be able to render a scene using a certain atmosphere or backdrop but have different controls over the light which is used for the skylight when doing GI. Recompiling the image and resetting the lighting I want is a pain. The final result has been posted in the gallery with a few additional changes. Many thanks to jangled for giving me lots of ideas for this image. -Kix

Kix, I can see a difference from 1 to 4, but only in the light from underneath, not the sky... anyway, that is beside the point. You are saying you want better controls over the sun and atmosphere, without using lights. I remember the old days of having to use loads of lights, all adjusted to different levels to light a scene just so. Now it is easier. I like the ability to not have shadows effect a particular object in the scene - wow! Nice presentation. I started 3d using Extreme 3D by Macromedia. Anyone remember that old app.?

To me the result in 4 looks just like a warming filter having been used. Would not a separate light, of that warmer colour, directed at the tower, with light range limited, have the effect you need? I like your solution all the same.

Sorry if I am going down a different thought track, the two imges show A--the default lighting render. B--With adding a Warm Bulb light into the default lights approximate location. No fiddling other than warming the the new Bulb light.

Message edited on: 02/19/2006 19:25

And B

I guess I've been lighting in the real world too long. To my eye, in each case the original skylight looks correct, and the warmer version looks off. At least in the "B" case lower, it is obvious there is a light involved (it does make my mind's eye wonder what this warm-colored object is that's casting this indirect light...) In the above set of four, the warm tower with the cool sky looks downright peculiar.

I agree with nomuse.

Along similar lines, when I use HDRI I wish I could tell Carrara to ignore the colors in the image. As someone else stated a while back, the sky is blue over our heads, and yet we don't all look like Smurfs. I'd like a colorful HDR backdrop and greyscale illumination from that same HDRI.

#1 is actually a more realistic scene than #4. A brighter Sun would make the sky brighter and wash out the Moon. Maybe Carrara could use some color filters to put over the camera lens to get the effect you want, like photographers use. Maybe Carrara has this already?

I use HDRI's for my backgrounds all the time with the skylighting turned off. I just use distant lights instead. This works great for objects that aren't reflective, like human skin. No smurfing.

Message edited on: 02/19/2006 23:36

I like the warmth and colorization of the object in image #4 better than #1, but as mentioned, the intensity of the sunlight does not jive with the darker blue sky. I don't like how the skylight has tinted the object blue in post #1 either though. A real sky doesn't cast blue light. hehe. If you use a brighter sky, then #4 is the more pleasing render.

Actually the atmosphere DOES tint objects blue, but getting the right lighting is going to be tricky no matter what.Usually, you are going to have something in mind...that's the point anyway. That's why photographer's use filters(That would be cool to have btw).I think #1 does look more accurate. That sky looks pretty dark w/ the moon and that tower is up there so to me the blue effect would definitely be there.Having the brighter warmer tower while nice(in seperation of figure/ground)doesn't look accurate to me either.

Have you tried changing the color of the sun? If you tint it a tiny bit it will affect your image quite dramatically and can yield interesting results. This example is extreme green.

"Actually the atmosphere DOES tint objects blue" Not nearly as dramatically as the skylight in Carrara. Let's not forget what's making the sky blue in the first place, which is sunlight. Take that away, and the atmosphere has no real color at all. So in my opinion, the sunlight should be the primary source of color tint on objects (depending on their reflective/refractive/and IOR properties).

Well,it's all a sim anyway.I didn't feel it was 100% accurate, just more so than 4.

"Take that away, and the atmosphere has no real color at all."
LoL, yeah take it away and you don't have much. Altho it is the gas molecules that work w/ the illumination. You gotta have both.Can't have a rainbow w/o a prism.

Yeah steama, that's really what it is about. What you choose. It's all about perception, some realistic things don't really seem that way to us when we see an image of it.It would be nice to have a polarizing filter for the camera tho.

Message edited on: 02/20/2006 21:08

In direct sunlight, the slightly yellow light of the sun pretty much overpowers the bluish color (or colour, if you prefer) of the sky. Step into deep shade, and you just get the bluish cast of the sky without the direct sunlight, hence the need to use the 'shade' white balance setting on your camera, to filter the bluishness (is that a word?) out. If you don't include a sun (or strong distant light) in your scene, what you are creating is a shade lighting situation, which realistically should have a bluish cast. Maybe the thing to ask Eovia for is the equivalent of tungsten/fluorescent/daylight/shade camera filter settings?

rj

Not to get too far off topic (or maybe back to the topic) but the point of the original thread is that I would like more control over the GI lighting sources. The realism of this exact specific image isn't what I was really concerned about (although I have been quite interested in the comments on that end). The comments in this thread have been great and I have learned. Just wanted to make it clear about what I was wanting as a possible change in Carrara. Thanks for all the comments. -Kix

Well, throw your money in the wishing well or water tower as the case maybe :)That would be nice, but I have so many other things I think that carrara needs more so.