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From: Ross Litscher
Subject: sphere sweeps and render time
Date: 7 Dec 2002 13:01:48
Message: <3df2378c$1@news.povray.org>
Hello all. I'm working on a little model of a lamp which uses sphere_sweeps.
Getting very low PPS in the first part of the image where the sphere sweep
isn't visible, i began to wonder why this is so. If I take the sphere sweep
out, render time increases a lot. the sphere sweep and texture is as follows
if it helps/matters, if not, ignore the code. I am using radiosity, but the
slow down occurs with or without radiosity. Please note if you try rendering
this, i use z as the "up" vector.

With the sphere_sweep i get about 30 PPS and without it I get 340 PPS, and
this is where there is nothing but a blue wall with just a simple pigment
{ rgb <0.05, 0.30, 0.80> }. So my question is, if its not apparent yet, why
does a sphere sweep affect the render time so much even when it is not
currently rendering any part of the sphere_sweep? Is there any way to reduce
this affect (i'm no master pov'er, i don't know such things)

thankyou,
ross

/****************************************************/

/* texture */
#declare shiney_black_iron =
texture {
  pigment {
    granite
    color_map {
      [0.0 rgb <0, 0, 0>]
      [0.4 rgb <.1, .1, .1>]
      [0.5 rgb <.3, .3, .3>]
      [0.6 rgb <.2, .2, .2>]
      [1.0 rgb <.05, .05, .05>]
    }
  }
  finish {
    phong 0.38
    phong_size 34
    specular 0.35
    reflection 0.15
  }
  normal {
    granite
  }
  scale .4
}

#declare lamp_post =
sphere_sweep {
  cubic_spline
  51
  <0.00 , 0.00 , 5.00>, .1
  <0.00 , 0.00 , 5.00>, .1
  <0.00 , 0.00 , 3.25>, .1

  /* crimp 1 */
  <1.00 , 0.00 , 3.00>, .1
  <0.30 , 0.30 , 2.95>, .1
  <0.00 , 1.00 , 2.90>, .1
  <-0.30, 0.30 , 2.85>, .1
  <-1.00, 0.00 , 2.80>, .1
  <-0.30, -0.30, 2.75>, .1
  <0.00 , -1.00, 2.70>, .1
  <0.30 , -0.30, 2.65>, .1
  <1.00 , 0.00 , 2.60>, .1

  /* small straightaway */
  <0.00 , 0.00 , 2.55>, .1

  /* crimp 2 */
  <0.00 , 0.00 , 1.60>, .1
  <1.00 , 0.00 , 1.60>, .1
  <0.30 , 0.30 , 1.55>, .1
  <0.00 , 1.00 , 1.50>, .1
  <-0.30, 0.30 , 1.45>, .1
  <-1.00, 0.00 , 1.40>, .1
  <-0.30, -0.30, 1.35>, .1
  <0.00 , -1.00, 1.30>, .1
  <0.30 , -0.30, 1.35>, .1
  <1.00 , 0.00 , 1.30>, .1

  /* long straightaway */
  <0.00 , 0.00 , 1.00>, .1
  <0.00 , 0.00 , -2.0>, .1
  <0.00 , 0.00 , -2.95>, .1

  /* base */
  <.75, 0, -2.95>, .1
  <1.5, 0, -3.0>, .1
  <0, 1.5, -3.0>, .1
  <-1.5, 0, -3.0>, .1
  <0, -1.5, -3.0>, .1

  <1.45, 0, -2.9>, .1
  <0, 1.45, -2.9>, .1
  <-1.45, 0, -2.9>, .1
  <0, -1.45, -2.9>, .1

  <1.4, 0, -2.8>, .1
  <0, 1.4, -2.8>, .1
  <-1.4, 0, -2.8>, .1
  <0, -1.4, -2.8>, .1

  <1.35, 0, -2.7>, .1
  <0, 1.35, -2.7>, .1
  <-1.35, 0, -2.7>, .1
  <0, -1.35, -2.7>, .1

  <1.3, 0, -2.6>, .1
  <0, 1.3, -2.6>, .1
  <-1.3, 0, -2.6>, .1
  <0, -1.3, -2.6>, .1

  <1.25, 0, -2.5>, .1
  <0, 1.25, -2.5>, .1
  <-1.25, 0, -2.5>, .1
  <0, -1.25, -2.5>, .1

  translate <0, 0, 3>          /* top of this object is at 10, bottom is at
0 */
}


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From: Christopher James Huff
Subject: Re: sphere sweeps and render time
Date: 7 Dec 2002 13:31:20
Message: <chrishuff-51A024.13281607122002@netplex.aussie.org>
In article <3df2378c$1@news.povray.org>,
 "Ross Litscher" <lit### [at] osuedu> wrote:

> With the sphere_sweep i get about 30 PPS and without it I get 340 PPS, and
> this is where there is nothing but a blue wall with just a simple pigment
> { rgb <0.05, 0.30, 0.80> }. So my question is, if its not apparent yet, why
> does a sphere sweep affect the render time so much even when it is not
> currently rendering any part of the sphere_sweep? Is there any way to reduce
> this affect (i'm no master pov'er, i don't know such things)

Well, a sphere sweep is a difficult object to bound, POV probably just 
doesn't know the sweep is not visible. Sphere sweeps are just pretty 
slow, though I think there is work being done on speeding them up, with 
better bounding and other optimizations.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/


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From: Ken
Subject: Re: sphere sweeps and render time
Date: 7 Dec 2002 13:34:58
Message: <3DF23FB7.F7D16E4D@pacbell.net>
Christopher James Huff wrote:
> 
> In article <3df2378c$1@news.povray.org>,
>  "Ross Litscher" <lit### [at] osuedu> wrote:
> 
> > With the sphere_sweep i get about 30 PPS and without it I get 340 PPS, and
> > this is where there is nothing but a blue wall with just a simple pigment
> > { rgb <0.05, 0.30, 0.80> }. So my question is, if its not apparent yet, why
> > does a sphere sweep affect the render time so much even when it is not
> > currently rendering any part of the sphere_sweep? Is there any way to reduce
> > this affect (i'm no master pov'er, i don't know such things)
> 
> Well, a sphere sweep is a difficult object to bound, POV probably just
> doesn't know the sweep is not visible. Sphere sweeps are just pretty
> slow, though I think there is work being done on speeding them up, with
> better bounding and other optimizations.

It might even render faster with automatic bounding turned off.

-- 
Ken Tyler


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From: Ross Litscher
Subject: Re: sphere sweeps and render time
Date: 7 Dec 2002 14:01:47
Message: <3df2459b@news.povray.org>
"Ken" <tyl### [at] pacbellnet> wrote in message
news:3DF23FB7.F7D16E4D@pacbell.net...
>
>
> Christopher James Huff wrote:
> >
> > In article <3df2378c$1@news.povray.org>,
> >  "Ross Litscher" <lit### [at] osuedu> wrote:
> >
> > > With the sphere_sweep i get about 30 PPS and without it I get 340 PPS,
and
> > > this is where there is nothing but a blue wall with just a simple
pigment
> > > { rgb <0.05, 0.30, 0.80> }. So my question is, if its not apparent
yet, why
> > > does a sphere sweep affect the render time so much even when it is not
> > > currently rendering any part of the sphere_sweep? Is there any way to
reduce
> > > this affect (i'm no master pov'er, i don't know such things)
> >
> > Well, a sphere sweep is a difficult object to bound, POV probably just
> > doesn't know the sweep is not visible. Sphere sweeps are just pretty
> > slow, though I think there is work being done on speeding them up, with
> > better bounding and other optimizations.
>
> It might even render faster with automatic bounding turned off.
>
> --
> Ken Tyler

I don't really know what this entails. i just read how i can turn it off,
but then do i have to manually set bounded_by for the sphere_sweep? or do I
just leave bounding off alltogether? Thankyou all for the info.
sphere_sweeps are fun, too bad they take a bit of time to render :)

ross


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From: Ken
Subject: Re: sphere sweeps and render time
Date: 7 Dec 2002 14:10:56
Message: <3DF24823.843D8DED@pacbell.net>
Ross Litscher wrote:

> I don't really know what this entails. i just read how i can turn it off,
> but then do i have to manually set bounded_by for the sphere_sweep? or do I
> just leave bounding off alltogether?

Just leave it off and see if the render time decreases. Automatic bounding
is useful for most scenes and helps decrease render times. However, in some
cases where the geometry is very complex, it may actually increase the render
times and it helps to turn it off completely when this happens. You may also
try manual bounding but you may have limited success if your object is too
complex to bound by hand.

-- 
Ken Tyler


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From: Christopher James Huff
Subject: Re: sphere sweeps and render time
Date: 7 Dec 2002 16:09:08
Message: <chrishuff-A597C2.16060207122002@netplex.aussie.org>
In article <3DF23FB7.F7D16E4D@pacbell.net>, Ken <tyl### [at] pacbellnet> 
wrote:

> It might even render faster with automatic bounding turned off.

Depends on the exact situation...if it tests for the bounding for every 
pixel or nearly every pixel, turning the bounding off will not have any 
effect on the sweep tests, but will get rid of the bounds tests, making 
things slightly faster. Probably not enough to matter though.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/


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From: Ross Litscher
Subject: Re: sphere sweeps and render time
Date: 7 Dec 2002 18:42:05
Message: <3df2874d$1@news.povray.org>
"Christopher James Huff" <chr### [at] maccom> wrote in message
news:chr### [at] netplexaussieorg...
> In article <3DF23FB7.F7D16E4D@pacbell.net>, Ken <tyl### [at] pacbellnet>
> wrote:
>
> > It might even render faster with automatic bounding turned off.
>
> Depends on the exact situation...if it tests for the bounding for every
> pixel or nearly every pixel, turning the bounding off will not have any
> effect on the sweep tests, but will get rid of the bounds tests, making
> things slightly faster. Probably not enough to matter though.
>
> --
> Christopher James Huff <cja### [at] earthlinknet>
> http://home.earthlink.net/~cjameshuff/
> POV-Ray TAG: chr### [at] tagpovrayorg
> http://tag.povray.org/

aye. I tried turning bounding off and making my own (simple) bounding box. I
only waited for the first couple lines to make comparisons, but the
differences were negligable it seemed. They're all slow :) I'll be sure to
post my lamp to p.b.i since this is my first 4+ hour render (still going at
4.25 hours) in a long time. besides, its all hand coded which is also a
first for a somewhat complete object. its nothing special, but i just feel
like posting something!

thanks for the help christopher and ken!


ross.


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From: Apache
Subject: Re: sphere sweeps and render time
Date: 7 Dec 2002 19:07:15
Message: <3df28d33@news.povray.org>
Please post it! IMHO it's way too silent at pbi and pba! I post almost all
the crap I'm producing here heheheheheh :-)

Regards,
Apache

"Ross Litscher" <lit### [at] osuedu> wrote in message
news:3df2874d$1@news.povray.org...
> "Christopher James Huff" <chr### [at] maccom> wrote in message
> news:chr### [at] netplexaussieorg...
> > In article <3DF23FB7.F7D16E4D@pacbell.net>, Ken <tyl### [at] pacbellnet>
> > wrote:
> >
> > > It might even render faster with automatic bounding turned off.
> >
> > Depends on the exact situation...if it tests for the bounding for every
> > pixel or nearly every pixel, turning the bounding off will not have any
> > effect on the sweep tests, but will get rid of the bounds tests, making
> > things slightly faster. Probably not enough to matter though.
> >
> > --
> > Christopher James Huff <cja### [at] earthlinknet>
> > http://home.earthlink.net/~cjameshuff/
> > POV-Ray TAG: chr### [at] tagpovrayorg
> > http://tag.povray.org/
>
> aye. I tried turning bounding off and making my own (simple) bounding box.
I
> only waited for the first couple lines to make comparisons, but the
> differences were negligable it seemed. They're all slow :) I'll be sure to
> post my lamp to p.b.i since this is my first 4+ hour render (still going
at
> 4.25 hours) in a long time. besides, its all hand coded which is also a
> first for a somewhat complete object. its nothing special, but i just feel
> like posting something!
>
> thanks for the help christopher and ken!
>
>
> ross.
>
>


Post a reply to this message

From: Ross Litscher
Subject: Re: sphere sweeps and render time
Date: 7 Dec 2002 19:36:42
Message: <3df2941a$1@news.povray.org>
its still rendering! oh no! and i noticed a control point mistake in the
sphere sweep! ack!


ross


"Apache" <apa### [at] yahoocom> wrote in message
news:3df28d33@news.povray.org...
> Please post it! IMHO it's way too silent at pbi and pba! I post almost all
> the crap I'm producing here heheheheheh :-)
>
> Regards,
> Apache
>
> "Ross Litscher" <lit### [at] osuedu> wrote in message
> news:3df2874d$1@news.povray.org...
> > "Christopher James Huff" <chr### [at] maccom> wrote in message
> > news:chr### [at] netplexaussieorg...
> > > In article <3DF23FB7.F7D16E4D@pacbell.net>, Ken <tyl### [at] pacbellnet>
> > > wrote:
> > >
> > > > It might even render faster with automatic bounding turned off.
> > >
> > > Depends on the exact situation...if it tests for the bounding for
every
> > > pixel or nearly every pixel, turning the bounding off will not have
any
> > > effect on the sweep tests, but will get rid of the bounds tests,
making
> > > things slightly faster. Probably not enough to matter though.
> > >
> > > --
> > > Christopher James Huff <cja### [at] earthlinknet>
> > > http://home.earthlink.net/~cjameshuff/
> > > POV-Ray TAG: chr### [at] tagpovrayorg
> > > http://tag.povray.org/
> >
> > aye. I tried turning bounding off and making my own (simple) bounding
box.
> I
> > only waited for the first couple lines to make comparisons, but the
> > differences were negligable it seemed. They're all slow :) I'll be sure
to
> > post my lamp to p.b.i since this is my first 4+ hour render (still going
> at
> > 4.25 hours) in a long time. besides, its all hand coded which is also a
> > first for a somewhat complete object. its nothing special, but i just
feel
> > like posting something!
> >
> > thanks for the help christopher and ken!
> >
> >
> > ross.
> >
> >
>
>


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From: Ross Litscher
Subject: Re: sphere sweeps and render time
Date: 7 Dec 2002 23:36:17
Message: <3df2cc41$1@news.povray.org>
ah, its nice when outlook express actually has more messages from the
newsgroup to search through. I just found the "sphere_sweep woes" post from
september. thanks for helping me regardless of redundancy.

guess i'll be doing my searches on the web interface from now on. much more
thorough!


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