View Full Version : Mental Ray HDR Light Blobs

06-10-2010, 02:53 AM
My HDR rendering has light blobs: It looks like a disco light is lighting my HDR scene.

Is there a way to get it to look like Picture 1 without the blobs?

Test Scene File (http://www.mediafire.com/?sharekey=356a5a27a399746ac79b87b207592a1cd86363f7fe04abc4f1940a51b339e393) (.mb with .hdr file)
Resolution HDR is 640x640 (Kitchen Probe (http://www.debevec.org/probes/))

Picture 1: ( I like the BLOOM effect and I want to keep it)
http://img808.imageshack.us/img808/4800/blobbylighting.png (http://img808.imageshack.us/i/blobbylighting.png/)

Picture 2: (not good; too dark)
Final Gathering Quality filter set to 2 (under the Indirect Lighting tab)
It's much darker. The lighting doesn't match the HDR image behind it as well as Picture 1.
http://img180.imageshack.us/img180/3162/blobbylighting2.png (http://img180.imageshack.us/i/blobbylighting2.png/)

http://img822.imageshack.us/img822/9514/fgfeatures.gif (http://img822.imageshack.us/i/fgfeatures.gif/)

http://img822.imageshack.us/img822/4034/fgquality.gif (http://img822.imageshack.us/i/fgquality.gif/)

Indirect Lighting:
http://img812.imageshack.us/img812/9088/fgsettings.gif (http://img812.imageshack.us/i/fgsettings.gif/)

Test Scene File (http://www.mediafire.com/?sharekey=356a5a27a399746ac79b87b207592a1cd86363f7fe04abc4f1940a51b339e393) (.mb with .hdr file)
Resolution HDR is 640x640 (Kitchen Probe (http://www.debevec.org/probes/))

06-10-2010, 05:30 AM
Then, it looks like there's some pretty high dynamic range in the image. You might try FG rays of 1000. Try it at first with a density of 1 before you increase density.

Do you have data on the values in the hdr image? What is its resolution?

What version of Maya are you using? It doesn't look like 2011, so perhaps the builtin IBL option will not be there for you.

I can't find FG Rays.
It's Maya 2010.
Resolution is 640x640 (Kitchen Probe (http://www.debevec.org/probes/))
IBL is an option. Does it offer more control?

I've been using this tutorial (http://www.3dtutorialzone.com/tutorial?id=70).
It has an IBL option at the bottom. But I was going through the FG section first.

OK...here it is with your suggested changes. I can't find FG Rays. Which tab is it under?

http://img812.imageshack.us/img812/9985/blobbylighting3bart.png (http://img812.imageshack.us/i/blobbylighting3bart.png/)

That's definitely better.

Bart. I used your settings and then changed the following:

Final Gathering Quality > Filter =0;
Accuracy = 800;
Point Interpolation = 200;
Point Density = 3;
FallOff Start =5;
FallOff Stop =20;
Primary Diffuse Scale = 1;
Secondar Diffuse Scale = 2;
http://img811.imageshack.us/img811/8134/blobbylighting3bartback.png (http://img811.imageshack.us/i/blobbylighting3bartback.png/)

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06-10-2010, 05:30 AM
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