GI without GI??!!

[Dr. Ira Kane]

it's xsi tutorial so you'll get probably more help at xsi base.

[spurv]

ok ok i know, but what i mean is cant we do it in Maya?

[Dr. Ira Kane]

If you're asking about faking GI in Maya, sure it can be done in few ways, just search for stuff like GI_Joe, Dirtmap, Ambient Occlusion and you should have some threads to read explaining how to fake it,then you can simulate bounced light with manualy placed maya lights.

[playmesumch00ns]

This is not faking GI. From a quick skim of the tutorial he's doing this:

1) Bake direct lighting into vertices

2) Turn off direct lights and have each object do a full glossy reflection of the scene. This is the first bounce. Bake this into vertices too.

3) Repeat step 2 ad finitum.


A full glossy reflection is a final gather. So all he's doing is multi-bounce final gathering per vertex. You'd be far better off doing a photon map then doing a per-vertex final gather and reading that back in for your final render.

[joie]

Yes but, how do you do these things in MAYA?, I´ve never got vertex shading to work so..., any ideas?

[playmesumch00ns]

Yep I'm having the same problem right now. Vertex baking just doesn't want to work. AAARRRGRGGHHH!! I HATE MAYA!

[joie]

Yeah, you have to connect that "lightMapSampling" to the input of the "LightMapWriter", that´s what MR docs says, but, if you do it, MAYA says that that connection is illegal, so it stops render..., I don´t know what to do now.

:(

[playmesumch00ns]

The light map will just do texture baking won't it? Not vertex baking...

The problem with the connections is easily fixed... it's a stupid bug that Alias have blindly left in as far as I can see...

you should be able to fix it by editing your base.mi file. In the lightmap_write declaration, change the type of the "texture" and "input" things to shader instead of color texture and vector texture like they are by default.

please let me know if you manage to get vertex baking to work:)

[MCage]

Some days ago i was trying to do the same thing....very intersting, and the gi image quality seems very good .
Hope someone can help us out..:)
bye.

[Pai Mei]

3 point lighting can fake gi, producing soft shadows etc

[SpiralFace]

personaly I use the GI_Joe script found on Highend 3D to get a fake GI out rather quickly. It automaticaly sets up iether 12 or 64 directional or spotlights for both ground lights and skylights that are pointed in around your scean. It comes in a group so its easy to move the entire light set if your working with spotlights, it has its own window that alows you to change the settings on all the skylights, or ground lights at once, without going in and adjusting all the settings.

Its not without its flaws though. It SEVERELY increases the render time. (Although from what I'm told it actualy GREATLY reduces the render time of a real GI light set.) And I'm absolutely cirtain that there are BETTER ways of doing GI, but I've found that this seems to be the fastest way to get a good GI set down, adjusted, and rendered out. Its supper easy to use, and pretty self explanitory.

[failure]

please let me know if you manage to get vertex baking to work:)
What exactly is not working with vertex baking?

[digones]

I use dirtmap, and I recommend it.


Fast, good and easy. And it works both on mac's and pc's

cheers

[MCage]

The problem that i have with dirtmap is , if you put a light infront of your model, you will have the DirtmapShadow infront of the model too,where the light illuminate.. innaturally...

there is a way to fix that?,..to haven't the dirtmap shadows where the light bounce?

thanks..

[annaleah]

I use dirtmap, and I recommend it.


Fast, good and easy. And it works both on mac's and pc's

cheers
What channels do you drag the dirt map into for maximum results digones?

[MCage]

I use it in the ambient or in the diffuse one..

[annaleah]

I use it in the ambient or in the diffuse one..
Ok,thanks MCage.

[digones]

What channels do you drag the dirt map into for maximum results digones?


Hi Anna

Usually I use Dirtmap just like MCage said



cheers

[joie]

What this topic is about is the way to use that wierd "lightMapSampling" and that short of things, nothing to do with ways to do GI or use any plugins and anything else, please, focus on this terms and ask those GI-related on the maya rendering forum.

Has anyone manage to use the mentioned nodes?, i´m about to ask in the MR mailing list, but first I want to try something in a couple of days since I´m with no computer right now...

[jeremybirn]

The problem that i have with dirtmap is , if you put a light infront of your model, you will have the DirtmapShadow infront of the model too,where the light illuminate.. innaturally...

there is a way to fix that?,..to haven't the dirtmap shadows where the light bounce?
If you upgrade one step to using Final Gathering instead of Dirtmap, then you'll still get the occlusion effect like dirtmap, only it'll occlude different light from different directions - especially if you use bright incandescent geometry instead of a light to illuminate the scene.

Dirtmap (like ambient occlusion) darkens things based on proximity to any potentially occluding surface being nearby, without regard for direction, it would take FG (or other GI techniques) to correctly occlude different colored illumination from different directions.

-jeremy

[gga]

please let me know if you manage to get vertex baking to work:)
Easy. Just download MR_cpvPack from highend and read the docs.
Note that only meshes are accepted.

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