Light mapping

# 1 11-05-2005 , 12:24 PM

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Ran across a pic that had a "light texture map" applied to the model. How is this kind of mapping possible? Is it possible through texture mapping?

Sorry I could not supply the pic I saw, I lucked on to it and lost the web address, but here is a example pic from the movie TRON.

Last edited by THX1138; 05-12-2010 at 10:14 PM.

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# 2 11-05-2005 , 03:50 PM

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Hey, sorry I cant really answer your question, but I am a noob and dont really know what a lightmap is. Is it a type of map that simulates actual lighting on the object, sorda like bump maps?

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# 3 11-05-2005 , 04:39 PM

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Yeah, or so I have come to believe it is part of a texture file. Saw a model where a guy had texture designes that glowed. The guy said that he made a light map or glow map "if thats a better choice of words" to make the effect. The guy didn't mention what program he used ( probably light wave ), but I hope it can be done in Maya 6.5, the version I have.

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# 4 11-05-2005 , 09:25 PM

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i suspect it could be done since poweranimator, maya´s ancestor...

So... the lightmap per se is a fancy name for the map used to control that effect it in realtime shaders....

There are two ways to do that in maya:

1) The QD way
Just stick a texture into ambient (and optionally into glow). the intensity will control the amount of brightness.

2) the controlled way is lenghtier to explain than what i have time to, but you can do that and much more with the help of the rendernodes and the almighty F1 key.
Prepare your index finger and hit F1 because you´re interested in reading the shaders section and specially in knowing how to make a multiple shader. with the outer layer with color ambient glow and transparency each controlled with its respective fine tuned maps and then put another full shader underneath with its own full set of maps.

Last edited by dragonfx; 11-05-2005 at 09:28 PM.

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# 5 12-05-2005 , 08:47 AM

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Ok, here's what I came up with. I made 3 texture maps for this experiment. I made a color map, a bump map, which was used for bump displacement, and an ambient map, which was used for the light map. I think the results came out pretty good. I can't make the red glow illuminate the ground plane like I want, but I suspect there is an attribute node some where that can make it possible.

Anyway, let me know what you think.

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# 6 14-05-2005 , 01:14 AM

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I can see some reflectivity on the ground, maybe up the node for the reflectiviness for the plane.

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# 7 14-05-2005 , 07:04 AM

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I guess placing a couple of lights around the model would work. The main problem with the glow is that it's so deep within the model. I'm probably going to have to make a special node for it to get the glows to cast on the ground plane.

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# 8 16-05-2005 , 01:48 PM

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you should be able to make the light bleed into the plane with final gather...

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# 9 16-05-2005 , 09:37 PM

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I used Final Gather for the render. If there is a special attribute to object lighting from a texture map, please let me know. I am by no means an expert at Mental Ray.

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# 10 17-05-2005 , 02:26 PM

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not sure, but try to put omni light in the centre of the sphere, than put map on its color or intensity!
It will work for sphere shape but for others...

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# 11 17-05-2005 , 03:04 PM

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damn it isnt working, light spreads from centre so it doesnt fit sphere radius!
.....hmmm...you got me wonder,now I wont be able to sleep!

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# 12 18-05-2005 , 08:05 AM

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no atribute that i know of to affect just the projecting light...(not that im an ubermentalray user either XD)
but in mental ray you can take the intensity of the color beyond the normal range (that is the principle of hdri) you could make the gray part one shader with the red part turned to a transparency map and underneat a very very red shader that projected enough red to tint the plane.

qd pic so that u see what im talking about

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# 13 19-05-2005 , 09:10 AM

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Ah, success at last! I didn't have to use a layerded shader for the effect. There was an attribute after all. I adjusted the color gain attribute on the ambient texture. I also udjusted the alfa gain on my displacement map. Thanks for the advice anyways dragonfx.

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# 14 05-06-2006 , 01:20 PM

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Originally posted by THX1138
Ah, success at last! I didn't have to use a layerded shader for the effect. There was an attribute after all. I adjusted the color gain attribute on the ambient texture. I also udjusted the alfa gain on my displacement map. Thanks for the advice anyways dragonfx.

Originally Posted by

Can you show a pic of the attribute like above, if you don't mind? I'm trying to experiment this setup and for some reason, the light does not glow, more like just dull color. The color gain is at max and how you setup the displacement?

I did the other stuff on top and works fine with the layered shaders, but doesn't show deep hole where light glow and fade out.

I thought of something else, maybe you could use glow effect...but not good enough?

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