In article <3c3fa559$1@news.povray.org> , "Slime" <noo### [at] hotmailcom> 
wrote:

> And that doesn't explain why its bounding
> box *stops* including the origin when you remove any one of the three
> sphere_sweeps

Because of your bounding threshold?  If you reduce the number below the
threshold the bounding will go away.

As for the bounding itself, I think I have found a way how to place it
closer around the spheresweep.

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

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> Because of your bounding threshold?  If you reduce the number below the
> threshold the bounding will go away.

Sorry, I'm not sure what a bounding threshold is...

but maybe this will convince you: if you translate the shapes, their
bounding boxes should move with them, right? Try translating them all by
<1000,1000,1000> or something, and the bounding boxes will still include the
origin, I bet.


- Slime
[ http://www.slimeland.com/ ]
[ http://www.slimeland.com/images/ ]

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In article <3c40dcac$1@news.povray.org> , "Slime" <noo### [at] hotmailcom> 
wrote:

>> Because of your bounding threshold?  If you reduce the number below the
>> threshold the bounding will go away.
>
> Sorry, I'm not sure what a bounding threshold is...
>
> but maybe this will convince you: if you translate the shapes, their
> bounding boxes should move with them, right? Try translating them all by
> <1000,1000,1000> or something, and the bounding boxes will still include the
> origin, I bet.

I somehow get the impression you think I said the bounding boxes are tight.
However, with "While the bounding boxes can probably be changed for
efficiency" I wanted to express that they are in fact not as tight as
possible.  I am sorry I wasn't clear enough.  Either way, hopefully this is
fixed in the next beta, but as I don't have a lot of test scenes we will
just have to wait and see...

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

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"Slime" <noo### [at] hotmailcom> wrote in message
news:3c40dcac$1@news.povray.org...
> > Because of your bounding threshold?  If you reduce the number below the
> > threshold the bounding will go away.
>
> Sorry, I'm not sure what a bounding threshold is...

The number of objects in a scene it takes before automatic bounding takes
over, if so set in a INI.  Bounding_Threshold = 6

> but maybe this will convince you: if you translate the shapes, their
> bounding boxes should move with them, right? Try translating them all by
> <1000,1000,1000> or something, and the bounding boxes will still include
the
> origin, I bet.

I see that happening too (takes a large render for me to catch it before the
window draws over it), just not sure what to make of it.  I put a sphere
into a union with the sweeps but opposite of them to see if that would keep
the ordinary sphere's bounding box pinned to the origin too and it did not.
Not much of a test but just to see what would happen.

bob h

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Wasn't it Slime who wrote:
>but maybe this will convince you: if you translate the shapes, their
>bounding boxes should move with them, right? Try translating them all by
><1000,1000,1000> or something, and the bounding boxes will still include the
>origin, I bet.


Yes, they do still include the origin in the bounding box when
translated. 

        This scene

#declare This=sphere_sweep {
 linear_spline,
 2,
 40, 1
 50, 1
 translate <1000,1000,1000>
}

#debug "Min: <"
#debug str(min_extent(This).x, 3, 1)
#debug ", "
#debug str(min_extent(This).y, 3, 1)
#debug ", "
#debug str(min_extent(This).z, 3, 1)
#debug ">\nMax: <"
#debug str(max_extent(This).x, 3, 1)
#debug ", "
#debug str(max_extent(This).y, 3, 1)
#debug ", "
#debug str(max_extent(This).z, 3, 1)
#debug ">\n"

        Produces the output

Min: <0.0, 0.0, 0.0>
Max: <1051.0, 1051.0, 1051.0>

-- 
Mike Williams
Gentleman of Leisure

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"Slime" <noo### [at] hotmailcom> wrote...
>
> Confirmation?

Yes.

This is the same bug that can cause radiosity to be calculated incorrectly
for sphere sweeps!  Note that setting Bounding_Threshold to zero in the INI
file (or command line) will "fix" the problem.

-Nathan

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In article <3c4208c0$1@news.povray.org> , "Nathan Kopp" <nat### [at] koppcom> 
wrote:

> This is the same bug that can cause radiosity to be calculated incorrectly
> for sphere sweeps!  Note that setting Bounding_Threshold to zero in the INI
> file (or command line) will "fix" the problem.

Ah, good to know that my change in beta 10 then corrected that bug.
However, why does radioity depend on a tight bounding box...?

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

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"Thorsten Froehlich" <tho### [at] trfde> wrote...
> > This is the same bug that can cause radiosity to be calculated
incorrectly
> > for sphere sweeps!  Note that setting Bounding_Threshold to zero in the
INI
> > file (or command line) will "fix" the problem.
>
> Ah, good to know that my change in beta 10 then corrected that bug.
> However, why does radioity depend on a tight bounding box...?

You know, I don't really know.  That radiosity code is still a bit of a
mystery in some places.  All I know is that the bounding problems were
causing problems with radiosity, and fixing the bounding problems (by using
Bounding_Threshold=0) fixed the radiosity problems in my tests.

I just tested the latest version and it seems that the radiosity problem is
also now solved for sphere sweeps.

-Nathan

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Wasn't it Nathan Kopp who wrote:
>
>"Slime" <noo### [at] hotmailcom> wrote...
>>
>> Confirmation?
>
>Yes.
>
>This is the same bug that can cause radiosity to be calculated incorrectly
>for sphere sweeps!  Note that setting Bounding_Threshold to zero in the INI
>file (or command line) will "fix" the problem.

On my machine, setting bounding_threshold to zero causes scenes that
contain no objects to crash. [I wonder if this is the missing ingredient
which causes some people to have all their objectless scenes crash -
perhaps they have bounding_threshold=0 in their ini file for some
reason.]

It also doesn't "fix" the problem that the min_extent (or max_extent) of
the sphere sweep always includes <0,0,0>.

-- 
Mike Williams
Gentleman of Leisure

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In article <+cfY### [at] econymdemoncouk> , Mike Williams 
<mik### [at] nospamplease>  wrote:

> It also doesn't "fix" the problem that the min_extent (or max_extent) of
> the sphere sweep always includes <0,0,0>.

Yes, that is to be expected because the bounding box is an object property,
and bounding only makes additional use of this property, so it is always
available, regardless of the use of bounding boxes for acceleration.

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

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