Noob Question: Double Sided Lighting

[o-v]

change logic... light is a reflection phenomenon... if light hits an object its reflected (full eg. a 100% mirror) or absorbed - it gets colored...

if u lit an object from one side u just cant have the same amount of light being visible on the "backside" of the object unless its 100% transparent. so the complete ligt amount passes the object - in this case the object gets invisible or it has some refractional quality... but this wouldn be visible in an empty space eather.

if u want to have the same light situation from all sides u have to lit it from all sides...

EDIT: or the object emits light by itself... check incadescence... if it should be the only one object in the scene thats lit from all sides... just link the lights to that object, so only that one particular part gets lit...

[faultymoose]

Thanks for the words of wisdom, but unfortunately that's not a solution to my problem ;) Incandescence isn't an option either, due to the nature of the scene. I just require that the backside of the polygon be illuminated to the same degree as the front side - something like a translucence effect.

There are a billion ways to fake a billion 'unrealistic' phenomena in Maya, surely this is one problem with a solution.

[LehaS]

I m not totally aware of the look you are after...but you d better try using physically correct shaders to do it i guess, because translucency will never bring the same color to the back of the surface as some amount of it will be absorbed....Well if you are really fond of faking it then try this method with mib_twosided....front is original lambert, back is the same lambert piped through mib_color_mix shader in order to be able to modify the back surface independently of the front one....

Hope it helps somehow :)

http://i34.photobucket.com/albums/d147/leha_sokol/mix.gif

[o-v]

something like a translucence effect.

it was never my aim being a smart ass but as I understood your desire - translucense or translucense like effect will never give u the same light situation behind the object...

use simply more lights and link them just to that object...

or: what do u mean by "both sides"? i has to have the same diffuse or the same reflection/refraction effect? what shadow? none? or something like fg or gi effect?

u mean u move a camera around? or is there a mirror behind it? what is the reason? why to look for a fake, if u can manage it a simple way...

[faultymoose]

Hey o-v sorry if I seemed to be taking the piss, I wasn't :) I appreciated your response, I was just being cheeky :P

The issues are:

1) We cannot light both sides of the object (they are cards, attached to a character to simulate hair/fur etc.). Lighting must be kept as simple as possible.

2) We cannot use mentalRay.

3) We cannot incorporate another pass to bake the illumination and fake it that way.

At the moment, we can easily light a shot to look fantastic from a particular angle, but as soon as the camera moves and we can see behind the cards, they are dark and no longer match the base surface. The cards are lambert shaders with an alpha map.

If I can someway force the rear side of the card to receive the same illumination as the front side, without baking, our problems are solved :(

P.S. Sorry about the initial lack of information - I'm standing beneath a big, scary looking NDA and I'm not really sure what I'm allowed to talk about.

[Exo7]

Maybe drop the Lambert for a Surface shader, with, as LehaS stated, a double sided material (http://aniquito.com/forums/index.php?topic=79.0). Add the network a surface Luminance node to get correct illumination without the lambertian shading.

That is a guess only, I didn't try this myself but I think you should give it a try :)

[EDIT] In fact, the Surface Shader and Surface Luminance should be enough !

[o-v]

ok so no mr...

I guess your "cards" cause shadows on the surface attached to?

I would try that way (without any complicated shading network)

put some point lights inside that object and link it to those cards

no other object should be effected by the light

i think that way the cards should recieve light from inside the object. in this case the carrierer shouldnt cause any shadows or break the lit of the backsides... and u have a good control over the intensity...

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