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Thread: 100W Light Blub

  1. #1
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    Mario Pende

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    Default 100W Light Blub

    Source type: Point
    Distribution: Isotropic
    Magnitude: Luminous Intesity
    Candelas : ????

    I found reading Ls Help that one light blub has intensity of 139 cd. If I use this amount, the room stays dark.
    Help
    Beeeee!

  2. #2
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    Default Re: 100W Light Blub

    6000 cd
    Beeeee!

  3. #3
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    Majdi Hajjar

    Lebanon



    Default Re: 100W Light Blub

    A 100W bulb emits a flux of 1360 lumen (Osram lamp).
    This gives a uniform intensity in space of 1360/(4x3.14) = 108 candela. Which is not far from the value given in Lightscape.
    What is the size of your room?
    The height?
    What colors and reflectances are the ceiling, walls and floor?
    Then I can calculate the lux level on a horizontal plane (illuminance).
    To see something on the screen, just boost the brightness in the properties menu. This will only change the screen appearance without changing the real values.
    Hope it helps.
    Majdi Hajjar
    Lighting Designer

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    Default Re: 100W Light Blub

    Majdi, the room is 4x3 meters, height is 2,7 m.
    If I boost the brightness than I will have a problem. My materials are always set for brightness/contast level at 50/50 (default).
    Beeeee!

  5. #5
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    Default Re: 100W Light Blub

    This is Ls block that I used as a luminarie, its a 100W lamp. Point, isotropic distribution.
    The room is 4x3x2,7 m.
    Reflectance of materials around 70%.
    Also I made the cover of the lamp non occlouding, but still the room is black.
    Attached Images
    Beeeee!

  6. #6
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    Default Re: 100W Light Blub

    forgot 140cd intesity
    Beeeee!

  7. #7
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    Default Re: 100W Light Blub

    Any lightning designers that can help/explain this?!
    Beeeee!

  8. #8
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    Default Re: 100W Light Blub

    Are these like the real values you would get when illuminting a room with 140cd?
    Attached Images
    Last edited by del82; November 6th, 2006 at 05:23 AM.
    Beeeee!

  9. #9
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    Arnold Gallardo

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    Default Re: 100W Light Blub

    Hmm let me guess you are comparing your impression of a 100 watt lightbulb with your brain and eyes right as to what you get with your render ? have you actually considered how much exposure you will need to get a bright room with a camera?

    The reason it is dark is because of the tone mapping in LVS. The tone mapping in LVS is set for mean values rather than mapping the perceptually important tones hence LVS does not know which areas ARE IMPORTANT to YOU. It uses a very simple cut off rate of displaying the computed luminance. This is why the file-properties- tone adjustments are there for because only YOu can tell which areas of the scene are important to you.
    _ _ ______________ _ _
    Arnold Gallardo
    Visual Content Creator
    Technical Writer

    Author:'3D Lighting: History,Concepts
    and Techniques'

  10. #10
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    Default Re: 100W Light Blub

    o.k. I understand this taht I can control the level of brigtness to get disered results, but are thies the real values you would get?!
    Beeeee!

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