Hi,

Whats the difference between a group, union and merge???

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> Whats the difference between a group, union and merge???

spelling....


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Rick

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On Thu, 7 Jun 2001 18:39:31 +0100, Rick [Kitty5] wrote...
> > Whats the difference between a group, union and merge???
> 
> spelling....

Apart from the fact that a merge removes all internal surfaces, and a 
group and union don't.

In Moray the Group and the Union are identical as far as exported POV 
code goes.

Bye for now,
     Jamie.

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> In Moray the Group and the Union are identical as far as exported POV
> code goes.

If this is the case why is there basically two groups but one doesn't accept
splines or non-primitives...it doesnt make sense

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On Thu, 7 Jun 2001 22:03:24 +0100, "george ferguson"
<geo### [at] ferguson123freeservecouk> wrote:

>> In Moray the Group and the Union are identical as far as exported POV
>> code goes.
>
>If this is the case why is there basically two groups but one doesn't accept
>splines or non-primitives...it doesnt make sense

A group is a MoRay concept. IIRC you can place anything in a group -
camera, lights, etc. OTOH a union is a POV-Ray CSG concept, an 'or' in
boolean terms. Some of MoRay's primitives do not exist in POV-Ray and
MoRay converts them into POV-Code, but I guess they can't be used in a
union within MoRay simply because they are not POVish. MoRay converts
groups to unions anyway so I think Lutz left the union in for clarity.
As of merge, it's like a union without inner surfaces.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg

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"Peter Popov" <pet### [at] vipbg> wrote in message
news:eij0it4s735a2vhe6u21nsoq0a8p2qnhq5@4ax.com...
> On Thu, 7 Jun 2001 22:03:24 +0100, "george ferguson"
> <geo### [at] ferguson123freeservecouk> wrote:
>
> >> In Moray the Group and the Union are identical as far as exported POV
> >> code goes.
> >
> >If this is the case why is there basically two groups but one doesn't
accept
> >splines or non-primitives...it doesnt make sense
>
> A group is a MoRay concept. IIRC you can place anything in a group -
> camera, lights, etc. OTOH a union is a POV-Ray CSG concept, an 'or' in
> boolean terms. Some of MoRay's primitives do not exist in POV-Ray and
> MoRay converts them into POV-Code, but I guess they can't be used in a
> union within MoRay simply because they are not POVish. MoRay converts
> groups to unions anyway so I think Lutz left the union in for clarity.
> As of merge, it's like a union without inner surfaces.
>
>
> Peter Popov ICQ : 15002700
> Personal e-mail : pet### [at] vipbg
> TAG      e-mail : pet### [at] tagpovrayorg

thanks for making sense of that ;-)

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On Fri, 8 Jun 2001 15:56:37 +0100, "george ferguson"
<geo### [at] ferguson123freeservecouk> wrote:

>thanks for making sense of that ;-)

I hope I am indeed making sense. I haven't used MoRay since I
evaluated it back in '94 or '95. Modellers are no good for me :(


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg

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mensaje news:3b1fee1d@news.povray.org...
> > In Moray the Group and the Union are identical as far as exported POV
> > code goes.
>
> If this is the case why is there basically two groups but one doesn't
accept
> splines or non-primitives...it doesnt make sense

In my opinion, the sense of it is simple:
The CSG it's not only the union, but also merge, intersection and
difference. It's obvious you can not use Bezier patches nor mesh in
intersection and difference (almost in pov 3.1).
The Group is for these elements, and it exports them as an union only, (even
though it can contain CSG operations of intersection and difference of
primitives and other objects that support these features).
I think the distinctions are clear.

Just an opinion.

Txemi Jendrix
tji### [at] euskalnetnet

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Hi george ferguson, you recently wrote in moray.win:

> If this is the case why is there basically two groups but one doesn't accept
> splines or non-primitives...it doesnt make sense
Apart from what everyone else has been saying there is also a
historical reason in that lights (or was it cameras?) were not allowed
in unions in an earlier POV-Ray version. Moray used to extract the
lights and cameras (calculate the final matrix according to where in
the hierarchy it was) and export it as a top-level object. It doesn't
do that anymore.

- Lutz
  email : lut### [at] stmuccom
  Web   : http://www.stmuc.com/moray

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