I am trying to figure out how to use Global Illumination and Final Gather to my advantage. I have a small interior space that I cannot figure out.

To the left I have natural light.
The rest of the room is 3ds lighting.
The image is way too dark, and yet there are loads of lights.

Can anyone help me change these settings or tell me why i have these random ovals on the wall (to the right) and these pixels of rendered areas?

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Is this option deliberately on? (See Attachment)
You don’t need it if the FG map was saved using the usual way.

ivan

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Ivan,

This is what happens when i change that final gather setting. The sunlight is whispy and the rear part of the room is still very dark.

Please advise.

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If it was intentionally on, (that means the interpolation is achieved through the relatively older method “the radius interpolation”), everything is OK. Obviously the tutorial uses this method. Then the cause of the issue you are having is elsewhere.

I asked if the option is deliberately on, because if the FG map was saved and locked without that option and later you accidentally hit the box (which happens very oft) you can get unpleasant artifacts in the rendered image.

Anyway you can try this way: uncheck the “radius interpolation”, (the Interpolate Over Num. FG points, become active), Delete the FG map, generate another FG map and render again. Try to achieve the best possible result playing with the “Interpolate Over Num. points” method. I personally prefer it, but that doesn’t mean that the older one (the radius interpolation) is not a good one. These are just two opportunities. Sorry if I mislead you.

ivan

I’ll insert my two cents.  Since Ivan is covering the FG, I’ll go over your GI settings.

Max Num. Photons per Sample: you have 4000, which may be a little high.  500 is default, and I rarely change it.

Maximum Sampling Radius: you have 1 inch, which IMO is way too low.  This value defaults to 1/10th the size of your scene.  Ideally, you want your photons to just overlap.  Interiors, I usually set this to 4 - 6 feet.  I wouldn’t go less than 6 inches.

Average GI Photons per Light: you have 200,000.  This also is a bit high.  I’ve had problems saving photon maps when they get too large (ie, too many photons shot).  In a smaller space like this, I’d use a maximum of 20,000, and typically would go as low as 8,000 photons.

I’ve also gotten into the habit of checking the box for Merge Nearby Photons (saves memory) and setting this low, like 1 inch.  It helps with the photon map size.

I also see that your Image Precision (antialiasing) is set to the max.  That really slows things down, and I never change it unless I encounter major aliasing problems.  I stick with the default Medium (1/4, 4) for nearly all my renderings.

Start with adjusting some of these settings, and see how things turn out.

3DS Max Design 2011 64-bit - Advantage Pack
Dell Precision T5500, Dual Six Core Xeon X5650 @ 2.67GHz, nVidia Quadro 5000, 24 GB RAM, Win 7 Enterprise 64-bit
Minneapolis, MN, USA

Thank you everyone,

I have decided to rebuild the lighting. After extensive watching of some online tutorials, i rebuilt the lighting to include the global illumination i was looking for. The pixeling had something to do with gi and fg. After rebuilding the lighting i reduced the amount of photons and had a better rendering. I still have lots to learn and alot of questions though.

for instance, my photon maps for other scenes are huge, some were 400 megs. how do i reduce this and get good global illumination?
Why am i getting these little white speckles on some materials and not others?
Why does creating a photon map sometimes render the image afterwards?
Why does my photon map hate me? lol.

Thank you for all of your help.

As Ivan said, more Photons means larger pmap.  There is also the option under GI to Merge Nearby Photons.  I’ve found that even setting this to 1” can reduce the pmap size considerably.  You can control the multiplier for Photons on a per-light basis, under one of the rollouts in the Modify tab.  I sometimes reduce this when a light is more for accent than illumination, so it shoots half or a quarter of the photons of other lights.

White speckles are usually related to Glossy samples, and sometimes are caused by self illuminated materials.  We use Fast Interpolate, and sometimes have to increase the number of points it uses to clear this up.

Not sure why generating a photon map would render the image too.  You hit the Generate Photon Map button, and it renders the scene?

Your photon map doesn’t hate you, it just doesn’t understand you… Maybe you two need to sit down and talk things out.  :)

3DS Max Design 2011 64-bit - Advantage Pack
Dell Precision T5500, Dual Six Core Xeon X5650 @ 2.67GHz, nVidia Quadro 5000, 24 GB RAM, Win 7 Enterprise 64-bit
Minneapolis, MN, USA