GI prelighting (for games) in Maya?

[DesignDawg]

Hey,

This may or may not help at all, but lower in this forum, there is a thread I was a part of a few days ago entitled "Ray Diffuse"....

The deal is, until Mental Ray 1.5 (on Maya 4.5 only), you can't use any of the "GI" techniques with different renderers or shaders, and bake the shadows like you can with regular Maya lights.
HOWEVER< in that thread, there is a trick for using a standard Maya ambient light (just one), to create VERY nice GI effects. It occurs to me, since this technique uses Maya lights only, you SHOULD be able to bake the shadows into the shader.

I'd love to know if it works, but I just don't have time right now to fool with it myself. Give that thread a look, and try it out. Please let us all know if it works. That would be a good trick for all of us to know, even for non-game projects.

Ricky
DesignDawg

[playmesumch00ns]

Yup you can of course bake standard Maya shadows fine. As far as RGB light maps goes, yes it could be done in realtime with multipass texturing but I'm not sure of what the performance hit would be.

If you were going to do it from a 'proper' GI solution like mental ray, you could always write a script to lock the camera gate to each individual poly and render out a complete set of individual poly lightmaps for the whole level?

[wedge]

Tekken 4 uses something like this. I believe Namco uses Maya.

[Per-Anders]

There was a tutorial on Highend3D to create a cheating version of GI/Radiosity using proximity nodes... thought it would probably be a little bit of a pain to set up on a full map it should bake though.


Darn i was going to go and get the link but unfortunately the whole HighEnd3D website is running incredibly slowly at the moment... it was called Farnell Box Simulation or something like that... hmmm can't remember... but when it's working properly you can go and check it out. Worth knowing just for the sake of it.

With regards has this technique been used before? Well... I'm pretty certain it has... most games nowadays work out the lighting dynamically to keep the memory usage to a minimum (otherwise you would have to have a seperate texture map for every poly in what could be a huge level and the file sizes would be immense... the alternative is vertex maped lighting, but that is of course dependent on the resolution of your models for any degree of realism and then you're dealing with which knocks back processing power of the target machine) to keep the speed of the game up. Remember most people out there don't have dual 2.5ghz P4's...

[sNaP]

I believe Silicon Knights used this technique in Eternal Darkness on the Gamecube. Overall, it looked really nice.

Doesn't the Quake engine do a radiosity pass of some sort when it compiles a map? Maybe that was something another company added on to it or something.

late!

[-wT-]

And the finnish (Wohoo!) game Max Payne also calculates radiosity when compiling it's maps, but I really haven't noticed the effect ingame ;) (Which you could say is a good thing)

[Flinch]

Originally posted by DesignDawg
Hey,

This may or may not help at all, but lower in this forum, there is a thread I was a part of a few days ago entitled "Ray Diffuse"....

The deal is, until Mental Ray 1.5 (on Maya 4.5 only), you can't use any of the "GI" techniques with different renderers or shaders, and bake the shadows like you can with regular Maya lights.
HOWEVER< in that thread, there is a trick for using a standard Maya ambient light (just one), to create VERY nice GI effects. It occurs to me, since this technique uses Maya lights only, you SHOULD be able to bake the shadows into the shader.

I'd love to know if it works, but I just don't have time right now to fool with it myself. Give that thread a look, and try it out. Please let us all know if it works. That would be a good trick for all of us to know, even for non-game projects.

Ricky
DesignDawg


you can't bake the shadows of the ambient-light-trick, because the maya-baker can't bake raytraced shadows. and the ambient-light-trick needs raytracing to calculate the shadows ...

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