On 26 Jul 1999 07:48:32 -0400, Nieminen Mika <war### [at] cctutfi> wrote:

>  Not really true. I wonder why this delusion persists.
>  See http://www.students.tut.fi/~warp/povVFAQ.html#csgspeed
>
>
>  (Everyone keeps saying that merge is (always) a lot slower than union,
>but no-one has ever said why. Or even proved it.)

Yeah, I have the VFAQ, Warp. I was referring to this particular case,
namely 100 or more transparent media-filled spheres. I agree that
merge can be faster in the some cases, particularly when there are a
lot of transparent objects close together (like 100-200 transparent
surfaces) and media. This is, you should agree, a rare occasion.


Peter Popov
ICQ: 15002700

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Nieminen Mika wrote:
> 
>   I tried this scene in this Sparcstation 4 rendering at 160x120 (it's a
> very slow machine...). I got these results:

  I would be interested in seeing your windows comarison. I ran one more
test using the previous test parmeters with the addition of media and
rendered at 640x480 to increase the render time. The difference between
merge and union was less than 5% for a 3.5 hour render time. The merge was
slightly faster.

-- 
Ken Tyler
  
mailto://tylereng@pacbell.net
http://home.pacbell.net/tylereng/links.htm

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Ken <tyl### [at] pacbellnet> wrote:
:   I would be interested in seeing your windows comarison.

  Yes, it probably is system and/or compiler dependant.

  Anyways, with semitransparent objects and lots of inner surfaces (which
are removed when merged), the merge operation is often (although not always)
faster than the union.
  I can easyly believe that with non-transparent objects merge may be a little
slower than union.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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I just had to laugh inwardly about all this talk in the newusers group.
It sounds so much like some advanced topic going on, for which there is
the appropriate group.


Ron Parker wrote:
> 
> On Sun, 25 Jul 1999 09:48:00 -0400, Dave Kreskowiak wrote:
> >In my experience, coincident surfaces tend to render a jittered imaged of
> >both textures, not a black spot.
> 
> Black spots (actually transparent spots) are fairly common.  They usually
> happen when you have an intersection involving coincident surfaces.  POV
> will find one or the other surface, then determine that that surface is
> "outside" the other surface and ignore that intersection.  It then goes
> on to find another intersection, but because it always starts looking at
> a distance of EPSILON along the ray from the last intersection, it misses
> the second surface at that point entirely, leaving a transparent spot
> that could show up as black under the right circumstances.

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/homepage.htm
 mailto://inversez@aol.com?Subject=PoV-News

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Bob Hughes <inv### [at] aolcom> wrote:
: I just had to laugh inwardly about all this talk in the newusers group.
: It sounds so much like some advanced topic going on, for which there is
: the appropriate group.

  Perhaps we should learn how to use the followup-to -field.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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Nieminen Mika wrote:
> 
> Bob Hughes <inv### [at] aolcom> wrote:
> : I just had to laugh inwardly about all this talk in the newusers group.
> : It sounds so much like some advanced topic going on, for which there is
> : the appropriate group.
> 
>   Perhaps we should learn how to use the followup-to -field.

...Or perhaps a few newbies will get the concept being discussed in this
thread so firmly pounded into thier heads they will never have to ask
similar questions again...

-- 
Ken Tyler
  
mailto://tylereng@pacbell.net
http://home.pacbell.net/tylereng/links.htm

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Hmmm, now this seems right. Original Group:povray.advanced-users (for
example) was left the same. Then the second header position (in Netscape
anyway) was set to Followup-To:povray.newusers and voila! I am now here,
from there. Everyone got that now? Stand back and watch the
mis-postings!

Please note that the intent is cause a redirection of message replies
into a different, possibly more appropriate newsgroup.


Bob Hughes wrote:
> 
> Wups! Well glad you said so, I looked at this and thought "Hey, OK! It
> works."
> What I had done is select Followup To: in a drop-down list where the
> povray.newusers was showing and then added this advanced group in after
> a Group: heading. Think I should have done the opposite. Will do that to
> this posting and send back to the newuser group under an appropriate
> title. Maybe...
> 
> Ron Parker wrote:
> >
> > On Tue, 27 Jul 1999 15:41:48 -0500, Bob Hughes wrote:
> > >Please forgive me if I've totally messed things up here but this is my
> > >first ever attempt at a "follow up" which Nieminen M. had mentioned.
> > >And if it works this might be as good a place as any to place this post.
> >
> > It didn't work.  It might look like it did, but it didn't.  You need to
> > set the Followup-To: header or it will default to sending followups
> > back to newusers.  slrn makes this easy; I don't know how easy it is with
> > Netscape.
> 
> --
>  omniVERSE: beyond the universe
>   http://members.aol.com/inversez/homepage.htm
>  mailto://inversez@aol.com?Subject=PoV-News

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/homepage.htm
 mailto://inversez@aol.com?Subject=PoV-News

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Ah ha! Seems my restrained worry was justified. I was expecting this
post to get out into the mainstream of the group for which it was
redirected to. And here I am back at the original thread where I had
begun my investigation of the Followup-To:
Well, to put an end of my feable tamperings I will now stop and simply
watch to see what happens because of this as others reply to the posts I
did here.
May have started a rip in the fabric of space and newsgroups, forgive me
please if I have.


Bob Hughes wrote:
> 
> Hmmm, now this seems right. Original Group:povray.advanced-users (for
> example) was left the same. Then the second header position (in Netscape
> anyway) was set to Followup-To:povray.newusers and voila! I am now here,
> from there. Everyone got that now? Stand back and watch the
> mis-postings!
> 
> Please note that the intent is cause a redirection of message replies
> into a different, possibly more appropriate newsgroup.
> 
> Bob Hughes wrote:
> >
> > Wups! Well glad you said so, I looked at this and thought "Hey, OK! It
> > works."
> > What I had done is select Followup To: in a drop-down list where the
> > povray.newusers was showing and then added this advanced group in after
> > a Group: heading. Think I should have done the opposite. Will do that to
> > this posting and send back to the newuser group under an appropriate
> > title. Maybe...
> >
> > Ron Parker wrote:
> > >
> > > On Tue, 27 Jul 1999 15:41:48 -0500, Bob Hughes wrote:
> > > >Please forgive me if I've totally messed things up here but this is my
> > > >first ever attempt at a "follow up" which Nieminen M. had mentioned.
> > > >And if it works this might be as good a place as any to place this post.
> > >
> > > It didn't work.  It might look like it did, but it didn't.  You need to
> > > set the Followup-To: header or it will default to sending followups
> > > back to newusers.  slrn makes this easy; I don't know how easy it is with
> > > Netscape.
> >
> > --
> >  omniVERSE: beyond the universe
> >   http://members.aol.com/inversez/homepage.htm
> >  mailto://inversez@aol.com?Subject=PoV-News
> 
> --
>  omniVERSE: beyond the universe
>   http://members.aol.com/inversez/homepage.htm
>  mailto://inversez@aol.com?Subject=PoV-News

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/homepage.htm
 mailto://inversez@aol.com?Subject=PoV-News

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Bob Hughes wrote:
> 
> Ah ha! Seems my restrained worry was justified. I was expecting this
> post to get out into the mainstream of the group for which it was
> redirected to. And here I am back at the original thread where I had
> begun my investigation of the Followup-To:
> Well, to put an end of my feable tamperings I will now stop and simply
> watch to see what happens because of this as others reply to the posts I
> did here.
> May have started a rip in the fabric of space and newsgroups, forgive me
> please if I have.

 If you had anything to add to this thread I suggest you just add it now, here,
otherwise I think it is pretty much dead :)

-- 
Ken Tyler
  
mailto://tylereng@pacbell.net
http://home.pacbell.net/tylereng/links.htm

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bob this should go to advanced

Bob Hughes wrote:

-- 
Cheers
Steve

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