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View Full Version : Can I get some help with Interior FG/GI and Lighting.


dweinin
07-02-2007, 05:15 PM
Hi everyone.
Running Maya 8.0 on Macbook Pro.

I am trying to light up and interior room scene with FG, GI and need some help. I feel like I'm almost getting it but am stuck a bit. I've attached some picts.

I have an interior room scene. It's was modeled in Feet but I've changed the scale to centimeters and scaled the entire scene down. It is now 20 x 15 units in centimeter scale.

I have 2 light sources.
1 spot light (about 38 units away)
1 area light (right outside the front window shining right into the building)
(See picture)

I have raytraced shadows on for both. Emit photons for both. And the area light is a regular maya area light with Mental Ray checked to on.

I can get really good lighting with these two lights. The photons are working well and the indirect lighting seems to be filling the room well. When I do tests with the photons, things look good to me.

My problem is the area light. If I get rid of it and just use the spot the scene lights up OK and the noise is gone! If it bring the are light back and use it I get much better lighting but my god the noise is a bit much. I figure the noise is coming from the soft shadows being created by the area light. So I cranked up the High level samples... still noisy... I cranked it up some more. The rendering I show here has a sample number of 250! Which seems to high to me. From everything I've read it seems like I shouldn't go above 8 or so. Even then at 250 the noise is very noticable.

The sampling in my Render Settings is set to min 0 and max 1.
And my FG settings are max 10% of the scene size and min 10% of the max. Basically- 2 and .2. 400 rays.

I've tried adjusting EVERYTHING and can't get rid of the grain unless i really crank things up and then the render time is too high. The attached render took almost 10 minutes. 640 x 480. The scene seems very simple too. Low polygon count. Flat DGS shader on everything with no glossy or specular on. I'm afraid of what will happen if I put on reflections and transparency maps.

I know FG and GI rendering using area lights takes a good chunk of time but 9 minutes on a simple scene seems a bit high to me. Is that a descent time? What else can I do to crank the render time down. How can I get rid of the noise?

Any help is awesome. Hope all of the above made scense and sorry for writing a novel to describe the problems.

Thanks
-Dweinin

slipknot66
07-02-2007, 05:51 PM
You need to increase the area light samples. Try 32.
Also use a direct light for the sun (with no photons)

dweinin
07-02-2007, 05:56 PM
Thanks.

The only problem with a directional light is that I can't get soft shadows out of it. Maybe it will still look good.

Is it OK ot jack up the samples to 32 on the area light. I've read not to take that over like... 8 or something.

However the render does look much better.

slipknot66
07-02-2007, 07:32 PM
To get the softshadows with the directional light you can increase the light angle to 1, and set the shadow rays to 6.Another thing you can do to get a correct light temperature, its connecting a mib_cie_d node to the light color of the directional light.Also if you are using IBL, you can connect the mib_cied_d node to the texture color.

coccosoids
07-02-2007, 07:46 PM
Hmm... isn't maya8 Powerpc only?! Better check, maybe that's why you are getting bad
performance...
And don't forget that you can raise the area light samples all you want, but untill you
haven't set good AA settings in the render globals it's useless.

dweinin
07-02-2007, 08:16 PM
Actually Maya runs pretty slick for on the MAC as far as I can tell.
The performance is getting better as I'm fine tuning the scene. I've got it down to about 3 minutes and looking much, much better.

What are the AA settings you're talking about.

Thanks Guys.

dweinin
07-02-2007, 09:24 PM
Ah... AA values... Anti Aliasing. Duh... Yeah I've got those set pretty good 0 and 2.

Thanks.

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