View Full Version : GI suddenly not working?

09-22-2005, 09:12 PM

I'm using Maya 6 unlimited here at work, just came back to it for another project. I'm trying to use GI and it isn't working at all. I swear I have all the settings right.

I did a test scene just to make sure and that still doesn't work. I have my spot light, I turn on GI/caustics, set the # of photons to 40,000. Set render options to preview GI and render. No bouncy-light whatsoever. I have on area light [rectangle], ray-traced shadows... All I get is an image with that uses shadows and regular lighting... When Maya does the processing for the photons it just goes right through it like it's not even evaluating...


09-23-2005, 10:41 AM
Which shaders do you use? ....if you use custom shaders than you have to add Photon Shader to the SG of your shader in order to control Photon behaviour during Photon tracing fase....

Otherwise photons wont be stored in the photon map

09-23-2005, 02:12 PM
For one custom scene, I had imported a model I did in modo, and exported to Maya as a .ma. It did have it's own custom shaders from modo.

So I tried a brand new scene. Created a poly cube, took off the top, threw in some poly spheres, added a spotlight with the correct settings (as far as I can remember), turned on GI... nada.

09-23-2005, 02:19 PM
Um... I think I accidently screwed up my Lambert1 shader, how do I fix it/initialize it?


09-23-2005, 03:25 PM
We'll I've made another scene, everything seems to be in order. I started a new scene, only Maya shaders and objects, nothing imported.

I turn on FG and GI and it just jumps straight to the the FG. It doesn't do the Photon emission calculation at all...

Any fixes for this?

09-23-2005, 03:51 PM
Do you have a light in the scene emitting photons?

09-23-2005, 04:55 PM
What are photons?

Um yes, I do. I'm sorry for the sarcasm but the thread title might indicate that I have actually gotten it to work before. :P

09-23-2005, 05:00 PM
Here's something, that might be a problem.

For some reason, the past few months that I've opened up maya, the Camera setting "far clip plane" is set to 10.00, even though the options state the default cameras should have it set at 1,000. Every time I go in Maya I have to set this if I create a new scene.

The other thing is that it takes a lot more "intensity" in the lights for them to actually light up the scene. I used to be able to use somewhere between 100-400. Now I have to use something like 10,000 just to light this simple scene, and for other things it's gone to the 100,000s... Quite distressing.

I'm not sure why but it's as if I have to model really large in maya now, because if I try to model small Maya does not like it. Sorry if I can't make it any clearer. I'm not even sure where to look to set it up so maya is using real world values like feet or meters. Instead it just uses 'units' based off the 'grid'

I'm thinking about giving Maya up all together but I have to render this stuff for work!

Thanks for your help.

09-23-2005, 05:17 PM
One more thing, and here's a real test of how messed up my Maya is (no idea how it got this way).

When I create a spotlight, it is TINY. Excuse me, I mean it's ****ing microscopic! Instead of it being the normal size, it is tiny. But perhaps it's the other way around... Maybe everything is HUGE, GIGANTIC! So big! And the light is the normal size, but dwarfed by these cosmic-sized objects...

Problem is that I scaled down my objects, but then the default cameras (Perspective) can't see up close well, and when zoomed in, the camera doesn't pan very fine, it is jumpy because everything is so tiny...

Can I just initialize Maya? Should I reinstall?

09-23-2005, 06:15 PM
Think I figured out the problem.

It has to do with this ridiculous size problem I'm having. I can make a spotlight, and it's tiny. Objects that are created are MUCH bigger than the light. The objects created (polys, nurbs, imported models) are about 100x bigger than they need to be (I'm guessing). So, when I use a light, and I have to set the intensity to 100,00 or whatever the case may be, the photons are just dying out before they can be used.

How can I get so that objects that are created are the right size?


09-24-2005, 05:50 AM
Glad you solved your problem

If you dont have lots of hotkeys assigned in the Hotkey Editor then you can just delete userPrefs.mel file. Then the next time you start MAYA it will autimatically create the default userPrefs.mel file with the default settings.So all your tool settings will be unified.Probably you have this "scale" problem since you have the wrong settings for creating 100x100 cube in your PolyCube Option Box. Reset them to default or just delete userPrefs as i mentioned and restart MAYA.

I have my units set to centimeters and model corresponding to this system

You could also run Diagnostic photon mode to preview yor photon tracing in the viewport.
MR Render Globals>Diagnostics>Diagnose Photons>ON

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09-24-2005, 05:50 AM
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