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John Bigboote

Klieg light with falloff...

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I am trying to get a spotlight (klieg) to have it's shadow lessen with distance... and I forget the trick! See image for illustration of what I am going after... should I use a regular bulb type light? is it the penumbra feature? How does one get this? (I recreated the effect I want in Photoshop here...)

TM_090.png

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Matt,

 

I believe you need to set the Kleig light to "Ray traced" , "Rays" to 1, and set its "width" to some large value depending on how severe you want the shadow diminish effect to be .

 

 

KleigShadow.JPG

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That will get you sharp edges. Rays > 1 will generate soft once but will take longer to render. (this is sometimes called area lights in other software if i am not wrong).

 

See you

*Fuchur*

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I'm not sure what your setting on Multipass is but I find that cranking that up a little will also help to blend the shadows.

 

Not quite related and it may not apply in this case but an additional blending trick I've been using is to turn up the transparency just slightly on the ground plane so that the camera's background color bleeds through to ground (as seen by the camera). Of course you have to turn off the Alpha Channel in order to get that to work BUT if using the alpa channel (in the case of comp'ing ) you can then easily change/tint the sky and ground to any color you want just by switching out your background. And this will of course work best with a background that is either a solid color or blurred considerable.

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That will get you sharp edges. Rays > 1 will generate soft once but will take longer to render. (this is sometimes called area lights in other software if i am not wrong).

 

See you

*Fuchur*

Thank- You, guys-

Gerald- I am intrigued by your 'area lights' approach... what do you mean by "Rays > 1" ...? do you mean set the rays to 'greater than' one? I don't always want sharp edges... would LOVE soft edges... so if I:

-change shadows to Raytraced.

-Set the kliegs width to a large( r) scale

-Set the number of rays higher(more rays = longer render but softer edges.)

-MultiPass render. (I guess I should do the 'Distribute in passes_ON option)

 

I am surprised that the 'falloff' has nothing to do with it.

BTW--- what does 'Penumbra' do...? manual speaks not of it.

 

I am trying it! Forum ROCKS!

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Gerald- I am intrigued by your 'area lights' approach... what do you mean by "Rays > 1" ...? do you mean set the rays to 'greater than' one? I don't always want sharp edges... would LOVE soft edges... so if I:

 

 

Rays > 1 does mean rays greater than 1

 

-change shadows to Raytraced.

-Set the kliegs width to a large( r) scale

-Set the number of rays higher(more rays = longer render but softer edges.)

-MultiPass render. (I guess I should do the 'Distribute in passes_ON option)

 

 

Multiple Rays will work in either Regular or Multipass.

 

With "distribute in passes" ON the total number of rays cast is the same either way.

 

With "distribute in passes" OFF I believe the multiple rays get duplicated in each multipass, which probably has no benefit since they are probably not jittered any differently.

 

 

I am surprised that the 'falloff' has nothing to do with it.

BTW--- what does 'Penumbra' do...? manual speaks not of it.

 

 

Penumbra ON adds a 9 (?) position jitter to a Z-buffered Kleig light (which has no "rays") to try to suggest the penumbral shadows of a wide ray-traced light.

 

With very wide lights the separate jitters become distinctly visible but the"softness" of the light can be upped to blend them together.

 

Wide light with Penumbra ON and 0% softness:

 

PenumbraZeroSoft.JPG

 

 

Wide light with Penumbra ON and 20% softness:

 

Penumbra20Soft.JPG

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For comparison....

 

Z-Buffered Klieg with Penumbra OFF but with 20% softness.

 

NoPenumbra20Soft.JPG

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THANKS! Great explanation as always, Robcat! It looks like Penumbra then is a Zbuffered approach to doing the same effect then... which begs more testing!

 

I like the look I am getting... I also enlisted a half-half IBL lighting scenario by lowering my lights (basic A:M default 3 light scheme with tweeks) by half and turning ON IBL at 50% strength and choosing a 4K 360degree lighting image from my Element3D provided environments.

TM_045.png

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