Hey....has any one had luck with indirect lighting....I cant seem to get good results....please let me know any setting that work for you.....here are two pics i did with different setting.....I think they both suck....I am not happy with the "GI" indirect lighting in carrara 3.....am i doing something wrong?

Here is the second render

I can't tell from your images what's not to like. I only get good results if I have the Lighting Quality set to Best and object AA/accuracy set to 1 pixel. I get very good results if I have Lighting accuracy set to 1 pixel instead of 16 pixels.

The rest I can do is hope I have decent materials/textures for my objects. They influence the lighting in a scene as well.

What is your light source? Sky light? Or a glowing plane outside your windows? What is the brightness of it? 100%? 150%? 750%? I've found that brightening up a light in Carrara 3 only makes a render brighter, not better.

Also. Make sure your objects are to scale. For example: the wall is 96 inches high and not 1.5 inches high. The rendered result is the difference between a dollhouse look and a real living area look. Some of the living rooms in the Scene Wizard are small enough to fit in a shoe box. Resizing them to full-scale improves their scene renders 10x.

I ordered the C3 Handbook from Amazon the other day. I hope it has similar details mentioned in it like the ones I've been discovering on my own through trial and error.

www.shonner.com

Message edited on: 08/28/2004 00:47

Did you turn off the ambient lighting in the scene settings? Am I right in assuming the light is from outside? If so, I always add just a little orange tint to the light to warm up thw feel a little. Actually these aren't all that bad, they look pretty accurate for a scene with no other light sources. Patrick Tuten

Thank you for the replys....shonner i will have to go get the book.....and patrick i left the ambient light setting on...should it be off?

I would tend to turn off the ambient lighting and add a bulb or spot light with its range set to light up the dark spots using very low brightness and have its "cast shadows" turned off.

Message edited on: 08/28/2004 13:29

thanks mike I will try that.

agreed... the first thing I do when starting a new scene is turn off the ambient lighting. One of these days I'll remember to set up a "starter" scene with all of these settings, instead of just hitting "new scene"...

Ambient lighting is basically the same thing as adjusting the brightness control on your monitor screen, it seems. It's probably the first and last setting you adjust. I turn it down if I'm after realistic lighting. But if I have an old clunker monitor, I turn it up a little so I can see a render better. www.shonner.com

Thanks Shonner....I have never turned it off before...but my monitor is new. Thanks for all your tips.

I have to beg to differ about ambient lighting, it's not like turning your monitor brighter. It is an overall actual amount of light in your scene. It will wash out shadows, take depth out of textures and reduce the contrast of your render. I haven't really found a good use for it except in quick test renders to see placement of objects better. I never use it in a final render. If you want back lighting, put in a key light and use a complementary color to your main light. I constantly see 3D renders where the main light source is white light. This almost never happens unless you're in a bathroom or something. If you want to add depth and richness to your scenes, use a little clor in your lighting. Also, with HDRI or GI specifically, ambient light is really unnecessary because you are already filling in your backlighting by bouncing off the surrounding surfaces. The default setting of 20 for ambient is quite high in my opinion. Study some of the scene wizard lighting setups to see some good basic examples of ways to light scenes. The proper lighting can really enhance a mediocre model, while poor lighting can ruin a great model. Just my opinion, I could be wrong.... Patrick Tuten

I've been trying out ambient lighting on living rooms I have similar to what res1yfb1 is using.

Different colors will colorize a render without adding shadows. It doesn't add light to a scene as far as I can tell. It just changes the color of the air, or ether ;), in a scene which changes the overall lighting color for everything in the room. White will whiten-up an a render. Gray is a neutral color that can be used to brighten or darken a render. Yellow/gold will color everything as though the sun is lighting the render.

In scenes where there is only indirect lighting from a single glow source, ambient lighting will probably have to be turned up 40-50% to see the textures of cave walls and sewage tunnels that would otherwise be pitch-black if ambient lighting was at 0%.

HDRI backgrounds include ambient lighting already using the various colors of their images. Ambient lighting can change the mood of an HDRI by adding more yellow, red, or blue to a scene. I think Sky Lighting has to be turned on though in order for light to shine through the HDRI. The Sky Light uses what ever color your HDRI's or backgrounds are using. So ambient lighting isn't really needed for such scenes unless minor color changing is also needed to enhance a render.

And yes, you are right Patrick.

www.shonner.com

Message edited on: 08/28/2004 21:38

I think of ambient light as "the light that's there before you add any lights." Years ago, when raytracers only made hard shadows and there was no GI, you had to put some ambient light into every scene or your shadows would be dead black. It was basically poor man's GI. So ambient light is definitely not necessary when using GI, although you can use it if you want, of course. Overall ambient light has the effect of reducing the contrast of a scene, because your ambient light setting defines how dark the darkest shadow can be. If your ambient light is a medium-dark grey, then your darkest darkest shadow will be that same medium darkness.

1.) If you have the time to beat on a render with your computer, turn ambient off. This also means that you have to put in all the real light sources the scene will have. HDRI is a great way to crack that problem if the HDRI "backdrop" is what you want. If not, add all the lights in the right places and right colors and the scene will start to look real. 2.) If you don't have time to beat on an image, you can fake radiosity light sources by adding more lights to the scene. In the image I've attached, the first image is only raytracing, no ambient, no anything! The second image has five lights added for radiosity fake out. I did this in Raydream so that has to be true! The third image was done as at est in C2 with GI. Once again, no ambient. 3.) You can use ambient and it won't wreck the realism of an image but the application space where that can be done is limited (typically to outdoors and typically at a very low level). Just three points from my experience. To get back to the origin of the thread, I think I'd like to know specifically what it is about the images that suck. Scale of the model does play a big role in how the render works out (something that isn't obvious I might add!).

Thank you all for your replys........What i think sucks about the pics i did is thet they do not look "REAL" to me.....but if you look at the new pic i did i am very happy with it...in this pic ambiant light is off.....let me know what you think.

also...I used no other lights..just one cube with glow...and HDRI..and ambiant off.

How did you get the light into this room? Did you remove the ceiling or the wall behind the camera? I'm curious if using a Gamma Setting or not makes any difference in Indirect Lighting renders. www.shonner.com

Hi Shonner This room has all four walls and a roof....i just put a glow cube at the top of inside the room and the other light is coming from the window wich is HDRI......I am very happy with the lighting on this pic.

Kirk, The lighting looks very good, I would be happy too. Mike

Re your reply to Shonner, I take it you're not using Gamma.

I've experimented with "torture-test" GI renders where the only illumination in the scene is from glowing objects. These are pretty extreme and may not be comparable to your more normally-lit scenes, but I've only gotten them to look decent with a Gamma of about 2.0.

Sorry...No I am not using Gamma...I tried it and did not like it...so i do not use it.

Yes, the bedroom scene lit by the glow-cube looks very good, very realistic.

To be honest I do not really understand the whole gamma thing. It looks to me that it has more to do with monitor calibration than it has creative use. And because I try to make use of Carrara for more than just looking at renders at my monitor, I stopped trying to find out what it is for. Does anybody here have a good use for it?

I do all my gamma correction post render. More control. -Kix

My video driver takes care of Gamma, so I've been turning it off in Carrara if I remember to. www.shonner.com

res1yfb1- I like the image, but the camera angle just doesn't seem realistic. Also on your door there is some major artifact, though this could be due to compression. Shadows also look a little off, for instance, by the shoes, I would expect a little darker shadows around the edges, of course this could depend upon the rooms lighting. Anyway, great render I like it:)