I was thinking about reflection and transparency effects the other day
and it occurred to me that many real objects aren't perfectly
transparent or reflective.. consider a moderately-polished wooden table,
or a lollipop. Yet, I know of no way to simulate this effect in POV-Ray.

My proposal is simple enough: the addition of a "blur" keyword, which
could be used inside of a finish (blurry reflection) or an interior
(blurry substance). I imagine that the easiest way to do this would be
with a variation on the focal blur or antialiasing code.

Of course, generating blur would increase render times, but.. well,
that's the price you pay...

-Xplo

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Xplo Eristotle wrote:
> 
> I was thinking about reflection and transparency effects the other day
> and it occurred to me that many real objects aren't perfectly
> transparent or reflective.. consider a moderately-polished wooden table,
> or a lollipop. Yet, I know of no way to simulate this effect in POV-Ray.
> 
> My proposal is simple enough: the addition of a "blur" keyword, which
> could be used inside of a finish (blurry reflection) or an interior
> (blurry substance). I imagine that the easiest way to do this would be
> with a variation on the focal blur or antialiasing code.
> 
> Of course, generating blur would increase render times, but.. well,
> that's the price you pay...
> 
> -Xplo

  There is a blurred reflection patch floating around somewhere but I don't
remember which one off hand.

-- 
Ken Tyler
http://home.pacbell.net/tylereng/index.html
I know you are but what am I ? <Unknown child>

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Ken wrote:

>   There is a blurred reflection patch floating around somewhere but I don't
> remember which one off hand.

It's in the superpatch: http://www2.fwi.com/~parkerr/superpatch/

Since Ron sent the source to the Superpatch to the Pov team it might
be included in Pov v3.5 but there are no gaurantees that it will.

-- 
Ken Tyler
http://home.pacbell.net/tylereng/index.html
I know you are but what am I ? <Unknown child>

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Ken wrote:
> 
> Ken wrote:
> 
> >   There is a blurred reflection patch floating around somewhere but I don't
> > remember which one off hand.
> 
> It's in the superpatch: http://www2.fwi.com/~parkerr/superpatch/
> 
> Since Ron sent the source to the Superpatch to the Pov team it might
> be included in Pov v3.5 but there are no gaurantees that it will.

Ah, but aren't the patches platform-specific?

Anyway, this would be a REALLY useful feature when you need it, and
(seems to me) should require minimal coding work, if the other blurring
code (focal and/or AA) is modular enough. It would seem to me like a
good idea to make sure that it gets in there...

-Xplo

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Xplo Eristotle wrote:

> Ah, but aren't the patches platform-specific?

  With this particular feature I don't believe that are any portability
issues involved. Where external libraries are involved such as using
windows .dll's then it is a problem but this addition to the Superpatch
is not one of them. The only issue is if it breaks something in the
official version or compromises must be made to include it.
 
> Anyway, this would be a REALLY useful feature when you need it, and
> (seems to me) should require minimal coding work, if the other blurring
> code (focal and/or AA) is modular enough. It would seem to me like a
> good idea to make sure that it gets in there...
> 
> -Xplo

  I agree that any new feature that proves itself useful should be added
to the official version if at all possible. Especialy when the programming
has already been done for the Pov Team.

-- 
Ken Tyler
http://home.pacbell.net/tylereng/index.html
I know you are but what am I ? <Unknown child>

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Xplo Eristotle <inq### [at] unforgettablecom> wrote in message
news:37A### [at] unforgettablecom...
> I was thinking about reflection and transparency effects the other day
> and it occurred to me that many real objects aren't perfectly
> transparent or reflective.. consider a moderately-polished wooden table,
> or a lollipop. Yet, I know of no way to simulate this effect in POV-Ray.
>
> My proposal is simple enough: the addition of a "blur" keyword, which
> could be used inside of a finish (blurry reflection) or an interior
> (blurry substance). I imagine that the easiest way to do this would be
> with a variation on the focal blur or antialiasing code.

    In the mean time, adding very small normal perturbations (eg, bozo 0.01
scale 0.00001) and antialiasing heavily will do quite a good job. Slow as
all-get-out, of course...but it is more or less how the Real World does it.

    However, as it is (a) a very useful part of the texture and (b) a time
sink, it would indeed be a good choice to build in.

    -Robert Dawson

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Another thought on "blur": some sort of blur_limit would be needed,
otherwise two blurred shiny objects would spawn exponential showers of rays.
(The perturb-and-antialias kludge does not have this problem.)



A demo of the kludge, which renders nicely at +A0.1 +AM2 +R3, and very
smoothly indeed at +A0.05 +AM2 +R4:

#include "colors.inc"

camera {
  location <0, 7, -14>
  direction <0, 0, 1.8>
  look_at <0, 0, 0>
}

light_source { <50, -200, -100> colour Gray70 }
light_source { <-20, 40, -20> colour Gray70 }
light_source { <100, 80, -200> colour Gray70 }

background { color MidnightBlue }

  #include "colors.inc"


          sphere {<-4,0,0>, 3  /*misty sphere*/
                pigment{color rgb 0.9}
                finish{reflection 0.3 phong 0.2 phong_size 0.1}
                normal{bozo 0.01 scale 0.00001}

            }
          sphere {<4,0,0>, 3   /*shiny sphere*/
                pigment{color rgb 0.9}
                finish{reflection 0.3 phong 0.2 phong_size 0.1}


            }
           plane{<0,1,0>, -3 pigment{checker color Red color White}}


-Robert Dawson

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The blurred reflection patch has a separate max trace level for the
reflections, as well as a separate ADC.

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