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View Full Version : LW lights: how to get a "real" look from them?


Bruzundanga
03-24-2003, 09:04 PM
Hello there,

I'm wondering.. is there a site or a book that covers the similarities between real lights and LW lights?

Let me explain better: I'm doing a walkthrough in a store, and I need to place several lights. I'd like to know the intensity of each light to simulate a real light. How much intensity of a area light I have to put to simulate a fluorescent light, for example?

I know the lights are difernt... not measured in candelas....

I'm only wondering...

maybe I'll have to make it all by hand...
HARD WORK!

:beer:

policarpo
03-24-2003, 09:31 PM
have a look in the Chapter 32 of your manual to see if there's anything in there which might help you. :)

leigh
03-24-2003, 09:32 PM
Jeremy Birn wrote a book on Digital Rendering and Lighting, it was published by New Riders. I haven't read the book myself, but I have seen parts of it, and it certainly looks like an excellent read.

It's not specific to LW, but I'm sure that it would be of help to anyone regardless of their choice of software :)

policarpo
03-24-2003, 09:34 PM
that is an awesome book. i learned tons from it. :beer:

i highly recommend it.

SplineGod
03-24-2003, 11:25 PM
Originally posted by Bruzundanga
Hello there,

I'm wondering.. is there a site or a book that covers the similarities between real lights and LW lights?

Let me explain better: I'm doing a walkthrough in a store, and I need to place several lights. I'd like to know the intensity of each light to simulate a real light. How much intensity of a area light I have to put to simulate a fluorescent light, for example?

I know the lights are difernt... not measured in candelas....

I'm only wondering...

maybe I'll have to make it all by hand...
HARD WORK!

:beer:
The problem is that Lightwave lights (or any 3d app) are not like real lights. Real lighting is far more complex and doesnt let you do things like exclude objects or selectively turn shadows on or off. There is no direct correlation in such a way that you could simply punch in numbers and it would work. In the real world you also have light bounce (radiosity) and a number of other factors etc etc. Your best bet would be to set up the basic lights and start doing test renders.

Tudor
03-25-2003, 08:07 AM
first.. without expensive GI you will not get correct lighting. Most of the light that lights a room for example, is not coming directly from the lightsource, but is rather bounced light.

inverse distance^2 is the most physically correct type of falloff.
It tends to be too white at the center though, because of the reason above. You need to krank it up way to high without GI to get enough light.

I found that using inverse distance (not ^2) works best for me.
setting the intensity to 50% of the watt of the lightbulb (30%) for a normal 60W lightbulb), and then using HDR exposure with a setting of 1 and 30%. ofcourse this is with GI.

The thing is that how bright something looks is all depending on your eyes. Go into a normal lit room from a sunny day. It will look almost pitch black. This is where I use HDR exposure. to simulate my eyes adjusting.

I am trying to set up a camera rig that takes into account all this. If you increase the dof by lowering the F-stop, motion blur distance should decrease etc.
Also working on trying to get certain wavelenghts of light reach further then other.
hope this helps..

Bruzundanga
03-25-2003, 11:10 AM
Hello there...

thanks you all for replying...

I'm interested in not use radiosity, because of the amount of render time it will consume... Do not know if the spinning trick would work for interior scenes (this is my very first try)....

know about boucing, but do radiosity works fine in interior scenes? thinking about the BIG shadow the walls will generate....

Or not, I don't know..

I was thinking in putting big area lights surrounding the scene, with the brighter in the roof and them, small spots.

more sugestions?

regrads

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