Is it necessary for POV-Ray to parse a file separately for each view of the
same scene?  Is there any way to "save" the result of the parsing to use in
repeated raytracings from different views?

Thanks in advance for any help with this.

-John VanZwieten

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Hmmm, to view other camera angles reparsing is needed because of the
change in rays going to/from objects.  Their profiles are always going
to be different, well that's my guess anyhow.  Parsing was improved as
I recall for multiple frames or renders of the same scene but think
you're talking about keeping a memory map of sorts which considers any
and all changes to camera position.  Of course if a scenes objects,
etc. change with time then the question is probably moot.

Bob

John VanZwieten <Joh### [at] emailmsncom> wrote in message
news:37e135f4@news.povray.org...
> Is it necessary for POV-Ray to parse a file separately for each view
of the
> same scene?  Is there any way to "save" the result of the parsing to
use in
> repeated raytracings from different views?
>
> Thanks in advance for any help with this.
>
> -John VanZwieten
>
>

Post a reply to this message

Bob Hughes <inv### [at] aolcom> wrote in message
news:37e14074@news.povray.org...
> Hmmm, to view other camera angles reparsing is needed because of the
> change in rays going to/from objects.  Their profiles are always going
> to be different, well that's my guess anyhow.

So parsing is view angle-dependent, rather than just scene-dependent.

> Parsing was improved as
> I recall for multiple frames or renders of the same scene but think
> you're talking about keeping a memory map of sorts which considers any
> and all changes to camera position.  Of course if a scenes objects,
> etc. change with time then the question is probably moot.
>

My situation is a "fly through" where the camera location/angle change but the
scenes objects do not.

Thanks for the info,

-John VanZwieten

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I'm not totally inner workings savy, but yes, from what I understand
the visible scene is calculated so the other stuff can be dropped out.
That makes for a change in parse I believe even when just viewpoint
changes.

Bob

John VanZwieten <Joh### [at] emailmsncom> wrote in message
news:37e142da@news.povray.org...
>
> Bob Hughes <inv### [at] aolcom> wrote in message
> news:37e14074@news.povray.org...
> > Hmmm, to view other camera angles reparsing is needed because of
the
> > change in rays going to/from objects.  Their profiles are always
going
> > to be different, well that's my guess anyhow.
>
> So parsing is view angle-dependent, rather than just
scene-dependent.
>
> > Parsing was improved as
> > I recall for multiple frames or renders of the same scene but
think
> > you're talking about keeping a memory map of sorts which considers
any
> > and all changes to camera position.  Of course if a scenes
objects,
> > etc. change with time then the question is probably moot.
> >
>
> My situation is a "fly through" where the camera location/angle
change but the
> scenes objects do not.
>
> Thanks for the info,
>
> -John VanZwieten
>
>
>

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On Thu, 16 Sep 1999 14:23:55 -0500, Bob Hughes wrote:
>I'm not totally inner workings savy, but yes, from what I understand
>the visible scene is calculated so the other stuff can be dropped out.
>That makes for a change in parse I believe even when just viewpoint
>changes.

Nope.  But vista buffers are view-angle dependent.  Still, there's not
currently any way to save the results of the parse.  My understanding
is that it wouldn't save as much time as it might seem anyway.

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John VanZwieten wrote:
> 
> Is it necessary for POV-Ray to parse a file separately for each view of the
> same scene?  Is there any way to "save" the result of the parsing to use in
> repeated raytracings from different views?
> 
> Thanks in advance for any help with this.
> 
> -John VanZwieten

There is no simple way how to do this.
POV-Ray is an offline program which reads
its input, computes a pretty output and
terminates. There is an animation loop,
but it is based on reparsing the scene.

I noticed some debates on a binary format
(this is probably what you mean) but it
was never implemented (binary triangle 
meshes are the only exception). Anyway,
a binary format would not lead to a 
significant parsing speedup.

You asked for "any way". OK, there is a 
way how to do a camera animation without 
reparsing the scene. This requires some
programming. You have to write a program
which mimicks POV-Ray but keeps running
unless told to terminate. Such an 
interactive POV-Ray must have an option 
to parse a new file after rendering a
frame, without destroying the original
scene which is still in memory. The new 
file will contain just the new camera.
That's it.

	y.

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Ron Parker <par### [at] fwicom> wrote in message news:37e14498@news.povray.org...
> On Thu, 16 Sep 1999 14:23:55 -0500, Bob Hughes wrote:
> >I'm not totally inner workings savy, but yes, from what I understand
> >the visible scene is calculated so the other stuff can be dropped out.
> >That makes for a change in parse I believe even when just viewpoint
> >changes.
>
> Nope.  But vista buffers are view-angle dependent.  Still, there's not
> currently any way to save the results of the parse.  My understanding
> is that it wouldn't save as much time as it might seem anyway.

Why not?  Parsing on a scene I'm working with takes >1.5 hours.

-John Van

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On Thu, 16 Sep 1999 14:36:02 -0500, John VanZwieten wrote:
>
>Ron Parker <par### [at] fwicom> wrote in message news:37e14498@news.povray.org...
>> On Thu, 16 Sep 1999 14:23:55 -0500, Bob Hughes wrote:
>> >I'm not totally inner workings savy, but yes, from what I understand
>> >the visible scene is calculated so the other stuff can be dropped out.
>> >That makes for a change in parse I believe even when just viewpoint
>> >changes.
>>
>> Nope.  But vista buffers are view-angle dependent.  Still, there's not
>> currently any way to save the results of the parse.  My understanding
>> is that it wouldn't save as much time as it might seem anyway.
>
>Why not?  Parsing on a scene I'm working with takes >1.5 hours.

The reason that was given the last time this came up was that profiling
shows that most of the time parsing is actually spent allocating and
shuffling memory around.  Of course this isn't true for all scenes, but
that's what "they" said.

Now that I have access to a copy of vTune for Windows, maybe I'll find 
a big scene to parse and see for myself.

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In article <37e149fe@news.povray.org> , par### [at] fwicom (Ron Parker) wrote:

> The reason that was given the last time this came up was that profiling
> shows that most of the time parsing is actually spent allocating and
> shuffling memory around.  Of course this isn't true for all scenes, but
> that's what "they" said.
>
> Now that I have access to a copy of vTune for Windows, maybe I'll find
> a big scene to parse and see for myself.

You can try pyramid.pov in the sample scenes. Just increase the recursion
level if you need a scene taking even longer to parse.


    Thorsten


____________________________________________________
Thorsten Froehlich, Duisburg, Germany

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But what when you render exactly the same scene at a different resolution?
Then it seems a pity that you have to render again.....

Sander

Bob Hughes <inv### [at] aolcom> schreef in berichtnieuws
37e143e8@news.povray.org...
> I'm not totally inner workings savy, but yes, from what I understand
> the visible scene is calculated so the other stuff can be dropped out.
> That makes for a change in parse I believe even when just viewpoint
> changes.
>
> Bob
>

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