Hello everybody: I've seen great images produced with the new GI renderer. I've tried using it but I just can't get the results I'm seeing in your images... By the way is it just me or is this renderer extremely slooow... I'm using Carrara on OSX (I think I saw a post in the Yahoo groups stating that there's a bug there and it is actually slower than OS 9...) What I'm trying to say with this is that trial and error is painfully slow, 'cause of this renderer. I have to wait to see the image, then do modification on the settings, then rerender (I use area render by the way, but it too is very slow. I'm using the default settings..) So any tips or tutorials on making a good image with GI?. Is this better for outdoor scenes or indoor scenes? How many lights should i use? or should I eliminate all lights and just crank up the global ilumination? What is a better ? Should I use an Environment map (atmosphere) or background image to get better results? or neither. This are just a few questions that I have... I have a Powermav g4 733 mhz with System X and 700something of RAM Thanks in advance.

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velarde: A week or so ago I posted an image done with Global Illumination and no lights, using the illumination from a background image. I also posted how I made the image. Its not a tutorial but it might help.

Hi Velarde, There's indeed a nasty bug on MacOSX which makes the photon calculation slower than on other OS . It should be fixed in a patch, i think . Have a look at the image i attach, it should guide you to optimize your render times . And here are a few tips : - disable GI when you don't need it ! If you're testing transparency, for example . You can add some ambient light temporarily to balance the loss of light . - disable bump, transparency, refraction and effects like that when you don't need them, too ! - make your lightning tests with the worst GI settings, it's enough . Better settings will give almost the same lightning with a better quality, that's all, so use good settings for your final renders only . I hope it helps a little . litst

Thanks for the time guys: Just one more question . Should I use several lights (for shadows) or just global iluminations (does it projects shadows...?) Or try for a balance of both? a little GI and one or two lights? Is global Iluminations supposed to be used instead of the ambient light? Every book that I've read says I should turn that one off and rely on lights that I create, Again thanks.

The global illumination renderer can be used with lights and no indirect lighting from a background or a sky dome (setting the intensity of these to 0 in the scene properties panel), and you will also get some natural looking results. Global Illumination simulates the way light bounces off different objects producing a more realistic look, and effects like radiosity (color bleeding), so it doesn't necessarily need light coming from a background or a sky dome. I think that a good balance of both light from specific light sources (bulbs, spots and distant lights) and a background or a sky dome is what you should shoot for. My example was just to test what would happen if you only used light from a background.

Litst is right for doing test renders. I think the two main things for fast test renders are no antialiasing and Indirect lighting quality set to preview. Here is a test render I did with no ambient light, one spot light ( not very bright ), and low to medium skylight. Indirect lighting will cause a relative increase in the amount of light in your scene depending on how many surfaces there are for it to bounce off of and fill in the shadows where raytracing did not go. Therefore, you don't need as much lighting as you are probably used to having. I would start with simple scenes with minimal lighting for learning purposes.

wow, Nice pic Patrick. This scene is rendered with low quality settings in GI? Thanks, Paul

No, sorry. The scene is not rendered with low quality settings. I was just telling how to to test renders, but the final render here is shown to explain how much or little lighting is needed when using GI.