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brainspoon
07-10-2003, 09:57 AM
as we all know, realistic lights have a quadratic/square falloff of their intensity.
the problem is when you place them too close to a surface you get a big white spot. this isn't the case with real life lights.
how can i mimic this behavior in 3d without intensity curves or such things. i use mental ray and the physical light shader.
i hope there is someone you help me there. my aim is to use realistic lights. somehow it must work. maybe with an other light shader or the IES light files that mental ray supports in its new version.

golem
07-10-2003, 10:21 AM
there are commercial solutions for photometric solid simulation, and this kinda softwares appear quite more like a cad cam than a 3D modelers.
in 3D software we assume that so called "skylight" aid us in raise global luminance level (ambien light), so we can put down just a bit light value (multiply rather than candles, lux, etc).
in fact i use to create a Daylight sistem in 3dsviz, study a 1st solution and after start putting in other lights.
computer graphic is a collection of algorithms we use in order to obtain an array of pixels we like (a nice image, i mean). for your goal i suggest you to leave common software and start exploring other solutions, but i cannot at the moment suggest you any product name.

golem

brainspoon
07-10-2003, 10:36 AM
my problem is not the global illumination. i only want to know how to get rid of the bright spots but keeping the square falloff of the lights.

Nosalis
07-10-2003, 10:47 AM
I`m not sure, If you`re using 3DS max5, but in 3DS MAX5 there is a exposure control, which is counting with GI Radiosity and this should maybe fix it.

It is balancig between shadow and light, and when you have with standard render white point on whall while the end is black, with exposure control, white point on wheel should be less shining, while black end is more "brighter" ... you see the part you haven`t seen before.

But it only works with physical right GI

golem
07-10-2003, 10:58 AM
no g.i.? you use photometric lights and no radiosity? mah...
if this is your approaching you can reduce light intensity and put a omnidirectional light no shadowcasting in order to increase global light. other solution... try to move a bit the light from the wall and design a little shelter, able to reduce the presence of light directly on the burned surfaces. but they are all workaround.
if you give a look at

http://www.cgarchitect.com

you will find that all the best studies use g.i. to obtain very photorealistic light solution, and their rendering look never "burned" by hard light.

now it's up to you...

hope to have been useful this time

golem

brainspoon
07-10-2003, 11:11 AM
i think you missunderstood. i used gi for this scene. but this is not of importance now. my only problem are the bright spots at the ceiling. that are standard lights with no photons emitted. you are right. be moving the ceiling up i could reduce this problem but my goal is to get it working this way. i want to understand the how and why. why do real lights do not overexposure the objects and distribute their light more evenly

BiTMAP
07-10-2003, 11:54 AM
turn up the ambience, turn down the light intencity and if you can cuase more bounces of the light... becuase even those spot lights seem to be a bit too bright (the way the light plays on the wall goes too far). Try that post a render, and I'll comment again.

brainspoon
07-10-2003, 12:19 PM
what do you mean with ambience? the settings in the mental ray sections of the materials?

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