On 1/23/2011 9:59 AM, Mr wrote:
>
>   stbenge<myu### [at] hotmailcom>  wrote:
>   >  A speed enhancement can be used to cut the render time down
>   >  significantly, with an arguably acceptable loss of accuracy. Under this
>   >  setup, two instances of the same object are used. One copy is visible,
>   >  uses blurred reflection, and has a no_reflection modifier applied to it.
>   >  The other copy uses non-blurred reflection, but with a no_image modifier
>   >  applied.
>
> Would there be a corresponding technique for speeding up blurred refractions?

There would, if POV had a "no_refraction" modifier. The best (and 
fastest) method for blurred refractions that I can think of is to bake 
all your scene's textures to meshes (and/or use Rune's illusion.inc), 
add a small surface normal to the refractive material and use high focal 
blur settings.

~Sam

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stbenge wrote:

> There would, if POV had a "no_refraction" modifier.

Even then a scene might not benefit much, as a second
blurred refraction object would need to be positioned
such that it appears in the first blurred refraction
for this technique to help. Refraction tends to be
less annoyingly recursive than reflection ;)

BTW I just tried: if the refraction leads to total
internal reflection the no_reflection modifier will
take effect.

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Le 23/01/2011 21:07, stbenge a écrit :
>>
>> Would there be a corresponding technique for speeding up blurred
>> refractions?
> 
> There would, if POV had a "no_refraction" modifier.


If you want no refraction, why don't you just turn the transmit & filter
to 0.0 (of the deepest texture in case of layered texture) ?

It seems so simple, I must have missed something.

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Am 24.01.2011 09:23, schrieb Le_Forgeron:

>> There would, if POV had a "no_refraction" modifier.
>
> If you want no refraction, why don't you just turn the transmit&  filter
> to 0.0 (of the deepest texture in case of layered texture) ?
>
> It seems so simple, I must have missed something.

You have indeed ;-)

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I posted that idea back in 2006. Anyone beat me to it? :)

http://news.povray.org/povray.binaries.images/message/%3Cweb.45509993b8175aee696633280%40news.povray.org%3E

Regards Roman

"Dave Blandston" <nomail@nomail> wrote:
> That's a great idea and it works like a charm, but...
>
>
http://news.povray.org/povray.binaries.images/message/%3C4baab97a%241%40news.povray.org%3E/#%3C4baab97a%241%40news.po
vr
> ay.org%3E
>
> -Just shows you guys are both very sharp!
>
> Regards,
> Dave Blandston

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stbenge <myu### [at] hotmailcom> wrote:
> At any rate, it's a good speed enhancement that needed more exposure ;)

There's a blurred reflection entry in the wiki thing describing how to use the
averaged normals, maybe that entry could be enhanced a little to describe the
speed enhancement trick as well. It's a really good tip!

http://wiki.povray.org/content/Knowledgebase:Language_Questions_and_Tips

Regards,
Dave Blandston

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On 1/23/2011 2:42 PM, Christian Froeschlin wrote:
> BTW I just tried: if the refraction leads to total
> internal reflection the no_reflection modifier will
> take effect.

It's good to know, though not something I would rely on ;)

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On 1/24/2011 3:25 AM, Roman Reiner wrote:
> I posted that idea back in 2006. Anyone beat me to it? :)
>
>
http://news.povray.org/povray.binaries.images/message/%3Cweb.45509993b8175aee696633280%40news.povray.org%3E

This is beginning to look like the "stacked planes" scenerio all over 
again :D

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On 1/24/2011 7:59 AM, Dave Blandston wrote:
> stbenge<myu### [at] hotmailcom>  wrote:
>> At any rate, it's a good speed enhancement that needed more exposure ;)
>
> There's a blurred reflection entry in the wiki thing describing how to use the
> averaged normals, maybe that entry could be enhanced a little to describe the
> speed enhancement trick as well. It's a really good tip!
>
> http://wiki.povray.org/content/Knowledgebase:Language_Questions_and_Tips

Hmm, I forgot all about the Wiki...

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clipka wrote:

> You have indeed ;-)

Actually I fell into the same trap when first reading
the original post, my mind completely flowed over trying to
understand why anyone would go to the trouble of averaging
256 reflective textures just to tell the object it would
be "not reflecting" after all ;)

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