POV-Ray : Newsgroups : povray.binaries.images : Blurred shadows? Server Time
15 Nov 2024 18:23:50 EST (-0500)
  Blurred shadows? (Message 1 to 7 of 7)  
From: Jörg 'Yadgar' Bleimann
Subject: Blurred shadows?
Date: 6 Oct 2005 22:47:22
Message: <4345e1ba@news.povray.org>
High!

Originally, I intended to reveal this only at a more advanced stage... 
but I got stuck with the shadows. I aimed at blurred shadows for the two 
lines of text, so I used a fairly large area_light made up of 50  by 50 
single lights. But then I found it very difficult if not impossible to 
make them *really* blurred - if I just enlarge the area light, shadows 
become thinner and thinner until they disappear completely, which is 
just logical. On the other hand, increasing the number of single lights 
does not help either, it just bogs down the CPU. Even at these 
comperatively moderate settings, the shadows of the lower line disappear...

Is there a way to blur shadows without post-processing at all?

See you in Khyberspace!


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From: Slime
Subject: Re: Blurred shadows?
Date: 6 Oct 2005 23:01:39
Message: <4345e513@news.povray.org>
If you have too much light hitting that back plane, it will drown out the
soft shadows.

Set the plane's ambient to 0 and diffuse to 1 in the finish{} block. Then
make sure your only light source is the area_light (if you want other light
sources on the text, put them in a light_group with the text). Set the
area_light's color to rgb 1, and if the direction to the area light from the
part of the plane we're looking at is about perpendicular to the plane, this
will cause a near perfect transition from white to black on the soft
shadows.

You may then want to raise ambient and decrease diffuse (keep them adding up
to 1 to keep the background white) to make the shadows lighter.

Also make sure you have circular and orient set in the area light.

 - Slime
 [ http://www.slimeland.com/ ]


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From: Skip Talbot
Subject: Re: Blurred shadows?
Date: 7 Oct 2005 00:09:00
Message: <4345f4dc$1@news.povray.org>
A different technique for achieving blurred shadows would be to use 
radiosity.  Its quite hard to make a point light produce fuzzy shadows. 
  On the other hand, its quite hard for radiosity to produce razor sharp 
shadows.  Try lighting your scene with pure radiosity with an ambient 
box replacing the area light.  If you keep the error bound high, say 1 
or so, the shadowed areas should be more than blurred.  This method will 
require much more tweaking than conventional lighting but I think you 
can definitely achieve what you are after.

Skip


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From: zorglub
Subject: Re: Blurred shadows?
Date: 7 Oct 2005 04:31:19
Message: <43463257$1@news.povray.org>

> High!
> 
> Originally, I intended to reveal this only at a more advanced stage... 
> but I got stuck with the shadows. I aimed at blurred shadows for the two 
> lines of text, so I used a fairly large area_light made up of 50  by 50 
> Is there a way to blur shadows without post-processing at all?
> 
> See you in Khyberspace!
> 

For this case, maybe place your plane far behind, and use focal blur ?


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From: Wagner
Subject: Re: Blurred shadows?
Date: 7 Oct 2005 09:00:01
Message: <web.4346707e168dcd23fb80c1bc0@news.povray.org>
light_source {
    LOCATION_VECTOR, COLOR
    area_light
    AXIS_1_VECTOR, AXIS_2_VECTOR, Size_1, Size_2
    [adaptive Adaptive] [ jitter ]
    [ circular ] [ orient ]
    [ [LIGHT_MODIFIERS...]
  }

try to raise the value of AXIS_1_VECTOR and AXIS_2_VECTOR.
What values are you using? And what's the distance of your light source to
the object?

Wagner


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From: Jörg 'Yadgar' Bleimann
Subject: Re: Blurred shadows?
Date: 7 Oct 2005 10:51:45
Message: <43468b81$1@news.povray.org>
High!

Wagner wrote:

> try to raise the value of AXIS_1_VECTOR and AXIS_2_VECTOR.

I tried this before... but now, with the diffuse value downed as 
recommended by Slime (which yielded a promising result), I would try it 
once again!

See you in Khyberspace!

Yadgar

Now playing: In the Beginning (Genesis)


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From: John VanSickle
Subject: Re: Blurred shadows?
Date: 7 Oct 2005 16:55:19
Message: <4346e0b7$1@news.povray.org>

> High!
> 
> Originally, I intended to reveal this only at a more advanced stage... 
> but I got stuck with the shadows. I aimed at blurred shadows for the two 
> lines of text, so I used a fairly large area_light made up of 50  by 50 
> single lights. But then I found it very difficult if not impossible to 
> make them *really* blurred - if I just enlarge the area light, shadows 
> become thinner and thinner until they disappear completely, which is 
> just logical. On the other hand, increasing the number of single lights 
> does not help either, it just bogs down the CPU. Even at these 
> comperatively moderate settings, the shadows of the lower line disappear...
> 
> Is there a way to blur shadows without post-processing at all?

I've found that using the area_light with jitter turned on, and with 
anti-aliasing set in the render will produce a soft shadow.  For speed 
use the adaptive option in the area_light.  This may produce splotching, 
which you can reduce by raising the adaptivity level.

Regards,
John


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