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1 Nov 2024 05:20:50 EDT (-0400)
  trace() question (Message 1 to 6 of 6)  
From: Alf Peake
Subject: trace() question
Date: 7 Apr 2001 09:32:03
Message: <3acf16d3@news.povray.org>
I'm playing with MPov 0.6a trace() for the first time. Do all tests
have to pass thru' origin? I have to move my object if I want
different?

--
Alf

http://www.peake42.freeserve.co.uk/
http://ourworld.compuserve.com/homepages/Alf_Peake/
gw3### [at] thersgbnet


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From: Chris Huff
Subject: Re: trace() question
Date: 7 Apr 2001 10:30:03
Message: <chrishuff-0F4349.09300307042001@news.povray.org>
In article <3acf16d3@news.povray.org>, "Alf Peake" 
<alf### [at] peake42freeservecouk> wrote:

> I'm playing with MPov 0.6a trace() for the first time. Do all tests
> have to pass thru' origin? I have to move my object if I want
> different?

No, what gave you that idea? You just have to specify a start point and 
a direction, the ray doesn't have to pass through the origin.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><


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From: Alf Peake
Subject: Re: trace() question
Date: 7 Apr 2001 19:47:58
Message: <3acfa72e@news.povray.org>
Thanks Chris, seems I was confusing direction with ray's end point or
destination. Back on track again now but I must cut out this snue
gliffing.

Alf


"Chris Huff" <chr### [at] maccom> wrote in message
news:chrishuff-0F4349.09300307042001@news.povray.org...
> In article <3acf16d3@news.povray.org>, "Alf Peake"
> <alf### [at] peake42freeservecouk> wrote:
>
> > I'm playing with MPov 0.6a trace() for the first time. Do all
tests
> > have to pass thru' origin? I have to move my object if I want
> > different?
>
> No, what gave you that idea? You just have to specify a start point
and
> a direction, the ray doesn't have to pass through the origin.


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From: Tom Melly
Subject: Re: trace() question
Date: 9 Apr 2001 04:51:28
Message: <3ad17810@news.povray.org>
"Alf Peake" <alf### [at] peake42freeservecouk> wrote in message
news:3acfa72e@news.povray.org...
> Thanks Chris, seems I was confusing direction with ray's end point or
> destination. Back on track again now but I must cut out this snue
> gliffing.

Hah! I ran into this misunderstanding. Drove me mad.


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From: Ron Parker
Subject: Re: trace() question
Date: 9 Apr 2001 09:16:40
Message: <slrn9d3dhq.31k.ron.parker@fwi.com>
On Mon, 9 Apr 2001 09:51:28 +0100, Tom Melly wrote:
>"Alf Peake" <alf### [at] peake42freeservecouk> wrote in message
>news:3acfa72e@news.povray.org...
>> Thanks Chris, seems I was confusing direction with ray's end point or
>> destination. Back on track again now but I must cut out this snue
>> gliffing.
>
>Hah! I ran into this misunderstanding. Drove me mad.

When I came up with the syntax, I considered the possibility that it would
drive people mad, but I thought that the alternative - that y'all would 
think the ray actually has an endpoint - was no better.  So I kept it the
way it is.

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.


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From: Tom Melly
Subject: Re: trace() question
Date: 9 Apr 2001 09:57:54
Message: <3ad1bfe2@news.povray.org>
"Ron Parker" <ron### [at] povrayorg> wrote in message
news:slr### [at] fwicom...
>
> When I came up with the syntax, I considered the possibility that it would
> drive people mad, but I thought that the alternative - that y'all would
> think the ray actually has an endpoint - was no better.  So I kept it the
> way it is.
>

Hmm, my confusion was/is whether the direction is relative to the start
point or relative to <0,0,0> (rather than whether the trace has an
endpoint).

A quick look at the relevant example in the help serves to remind me if I
think REALLY hard.


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