POV-Ray : Newsgroups : povray.general : Speed kills... Server Time
31 Oct 2024 21:29:30 EDT (-0400)
  Speed kills... (Message 1 to 5 of 5)  
From: gonzo
Subject: Speed kills...
Date: 7 Apr 2005 16:40:01
Message: <web.42559a64d7796c03a0c272b50@news.povray.org>
....any hope of getting an IRTC entry done in time...

I'm working on some smoke for a catastrophe so I defined three textures
which I combine on a pillar of spheres. Test renders on a few spheres
indicated it was slow but usable.  Rendering the column of smoke with plain
pigments substituted takes about 6 seconds, so the object itself isn't a
problem, but when I put the final textures on the column it gets sooooo
slooooww I can't believe it.  I started a render last night before I went
to bed, when I left for work this morning almost 8 hrs later it was only on
line 23.  And I still need to add radiosity.

Sorry, don't have the textures here at work, but they are something like:
texture {
  pigment {
    granite scale 3
    color_map {
      [0.00 rgbf 1] [0.30 rgbf 1] [1.00 rgbf <.960, .940, .910, .810>]
    }
    warp { turbulence 1 octaves 5 lambda 4 }
  }
  finish { ambient .1 diffuse .55 }
}

Any suggestions on how to speed this up?

I'm currently building the column in layers and applying the texture to each
layer as I go. Does applying the texture to the whole union vs individual
spheres vs layers of spheres make a large difference?

Does the ambient component in the finish affect speed? The textures all have
different ambient levels and it seems like the less ambient one is slightly
faster.

Alternately, does anyone have a fast smoke texture that works in POV 3.5?

At the current rate, I'll never get a render finished by the deadline.

RG


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From: Tim Nikias
Subject: Re: Speed kills...
Date: 7 Apr 2005 19:39:27
Message: <4255c4af$1@news.povray.org>
Well, for one, I'd just use transparency instead of filtering. Then, have
you switched off shadowing for the smoke?

What I did in my "Highnoon" Short (1st Place last round on IRTC :-) was to
use half-spheres, texture them, put them in a seperate lightgroup, have them
cast no shadows, and face the camera. To get shadows on the objects, I
textured another batch of half-spheres at the same locations, but facing the
main lightsource.

It all depends on what kind of scene you have and the lighting/shadowing, so
maybe using media inside of blobs would be even better than your current
technique...

-- 
"Tim Nikias v2.0"
Homepage: <http://www.nolights.de>


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From: King of the Sea
Subject: Re: Speed kills...
Date: 9 Apr 2005 14:15:00
Message: <web.42581a11fa06e7a13fda19ca0@news.povray.org>
Hi guys! I just registered! I don't know much about fur textures but I know
how to  do a sea scene, the source code is


       #include "colors.inc"
       #include "glass.inc"
       #include "metals.inc"
       background {color Navy}
       camera
       {
       location <0, 0, -3>
       look_at <0, 0, -5>
       }
      sphere {
    <-14, 10, -25>, 3
    texture {
      pigment { color Gray25 }
      normal {dents 2 scale.4}
    }
    }
      plane { <0, 1, 0>, -1
    texture {F_MetalA}
    pigment {
      checker Col_Glass_Clear, color Col_Glass_Clear
    } normal {wrinkles 100 scale.100}
    }
     plane { <0, 1, 0>, -2
    texture{F_MetalC}
    pigment {
      checker  Col_Glass_Bluish, Col_Glass_Bluish
    } normal {dents 10 scale.1}
    }
    plane { <0, 1, 0>, -2
    texture {F_MetalE}
    pigment {
      checker Col_Glass_Bluish, color Blue
    } normal {dents 10 scale.1}
    }
    plane { <0, 1, 0>, -2
    texture {F_MetalE}
    pigment {
      checker  Col_Blue_01, Col_Blue_03
    } normal {dents 10 scale.1}
    }

   light_source { <3, 3, 15> rgb 1 }
 /* This light source affects the moon in this picture*/  light_source { <7,
8, -20> rgb 10}
    fog {
    distance 150
    color rgbf<0.2, 0.2, 0.3, 0.5>
  }
  fog {
    distance 150
    color rgbf<0.1, 0.1, 0.3, 0.1>
    fog_type 2
    fog_offset 25
    fog_alt 1
  }


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From: gonzo
Subject: Re: Speed kills...
Date: 10 Apr 2005 16:32:23
Message: <42598d57@news.povray.org>
Tim Nikias wrote:
> Well, for one, I'd just use transparency instead of filtering. Then, have
> you switched off shadowing for the smoke?

Thanks for the comment. Transmit make a little difference, but not much. 
Haven't tried without shadows yet because the self shadowing is part of 
what makes it look good.  I'll try that though, and if its significantly 
faster maybe I can do something else to fake the shadows...

> What I did in my "Highnoon" Short (1st Place last round on IRTC :-) was to
> use half-spheres, texture them, put them in a seperate lightgroup, have them
> cast no shadows, and face the camera. To get shadows on the objects, I
> textured another batch of half-spheres at the same locations, but facing the
> main lightsource.

Hadn't thought about lightgroups, something else to try... may help with 
the self shadowing.

> 
> It all depends on what kind of scene you have and the lighting/shadowing, so
> maybe using media inside of blobs would be even better than your current
> technique...

Heh heh, I started down this path thinking textures would be faster than 
media...  Been experimenting with it, but my knowledge of media is thin 
at best. I'm likely to spend more time figuring out the media than I 
save in render time :-/

RG


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From: gonzo
Subject: Re: Speed kills...
Date: 11 Apr 2005 15:10:01
Message: <web.425aca90fa06e7a1a0c272b50@news.povray.org>
gonzo <rgo### [at] lansetcom> wrote:
> Haven't tried without shadows yet because the self shadowing is part of
> what makes it look good.  I'll try that though, and if its significantly
> faster maybe I can do something else to fake the shadows...

Well, that answers that! Using no_shadow renders about 90% faster... Doesn't
look near as good though, as the shadows define the billowiness (new word?)
and give it some shape.  Playing around now with a gradient texture_map
using a dark and light version of the texture to get back some of the
shape.  Looking at the finish Zaeger uses in his smoke from his nuclear
explosion too.  Adding brilliance helps.  Thanks Zaeger!

> Hadn't thought about lightgroups, something else to try... may help with
> the self shadowing.

Lightgroup didn't do much...

> Heh heh, I started down this path thinking textures would be faster than
> media...  Been experimenting with it, but my knowledge of media is thin
> at best. I'm likely to spend more time figuring out the media than I
> save in render time :-/

Media is working as expected... don't have anything I like yet, and its also
slow.

But I think I can get something workable in a texture by the deadline now,
so WOOHOO!  Thanks for all your help!

RG


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