POV-Ray : Newsgroups : povray.pov4.discussion.general : [SDL] New instruction - Automatically joining objects : Re: [SDL] New instruction - Automatically joining objects Server Time
18 Apr 2024 19:13:37 EDT (-0400)
  Re: [SDL] New instruction - Automatically joining objects  
From: Kelumden
Date: 24 May 2010 08:35:01
Message: <web.4bfa7242eb5f60cc8b9d68640@news.povray.org>
Warp <war### [at] tagpovrayorg> wrote:
> Steve <ste### [at] zeroppsuklinuxnet> wrote:
> > Nicolas Alvarez <nic### [at] gmailcom> wrote in
> > news:4b305906$1@news.povray.org:
>
> > > Kelumden wrote:
>
> > > I don't understand why union{} isn't enough for your needs...
> > >
>
> > I don't know if I'm getting him right or not but the way I understand it is
> > he wants an anchor in POV space where two objects meet, a bit like if you
> > stick a piece of blue tack to a table and then pull, strethc and twist it
> > (as long as you don't pull too hard), the blue tack will stay stuck to the
> > table in exactly the same spot, any action you perform on the blue tack
> > will have no resulting effect on the table but the table and the blue tack
> > will continue to be connected at the same point and covering the same area
> > of the table.
>
>   How does that differ from union{}?
>
> --
>                                                           - Warp

First, sorry for being so long in answering ...

It has nothing to do with union{}. union results in the object being considered
as one entity for rendering.
Here, the 'new' instruction allows someone to design an object centered around
the origin, then, without complex calculations, put it against another object.

If I were to rely on union, I would first have to carefully compute (the surely
go into a trial and error process) the transformation of the first object to
append it to the second.

We have here a computer who can perform all the calculations for us so it seems
to me quite reasonable to tell the computer: "take object A and put in on object
B so that point x of A merge with point y of B". You still need union{} to treat
the two assembled objects as one ...


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