The MegaPov glow feature has a size keyword which controls the size of the
glows as a scaling factor.

However, the apparent size of glows can also be controlled by adjusting the
color.

The code below shows that there's very little difference between multiplying
the size with a factor and dividing the color with the same factor. Try to
change the value M to values from 0.1 to 2.

#version unofficial MegaPov 0.7;
#declare M = 1;
glow {type 0 location -x color 0.1*M size 1}
glow {type 0 location +x color 0.1   size 1*M}
camera {location -4*z look_at 0}
box {x,x}

The code below shows that the same thing but in a different way. Here you
can change the M value from anything from 0.000001 to 1000000 and still the
difference is rather small.

#version unofficial MegaPov 0.7;
#declare M = 0.1;
glow {type 0 location -x color 0.1   size 1  }
glow {type 0 location +x color 0.1*M size 1/M}
camera {location -4*z look_at 0}
box {x,x}

So, what exactly is the point of the size keyword? How can it be used to
achieve results that can not be achieved with the color alone?

Rune
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In article <3a8ee7c7@news.povray.org>, "Rune" <run### [at] inamecom> 
wrote:

> However, the apparent size of glows can also be controlled by adjusting 
> the color.

With some glow types, the size keyword works by adjusting the color 
brightness, but it uses a different method for other glow types.


> So, what exactly is the point of the size keyword?

To adjust the size of the glow.


> How can it be used to achieve results that can not be achieved with 
> the color alone?

Depending on your glow type, the differences between the results can be 
extreme or nonexistent.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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"Chris Huff" wrote:
> With some glow types, the size keyword works by adjusting
> the color brightness, but it uses a different method for
> other glow types.
>
> Depending on your glow type, the differences between the
> results can be extreme or nonexistent.

Ah, thanks.

I will look more into this later...

Rune
--
\ Include files, tutorials, 3D images, raytracing jokes,
/ The POV Desktop Theme, and The POV-Ray Logo Contest can
\ all be found at http://rsj.mobilixnet.dk (updated January 28)
/ Also visit http://www.povrayusers.org

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