Lutz Kretzschmar wrote:
> 
> Hi Ken, you recently wrote in moray.win:
> 
> > I hate to burst everyones bubble here but CSG operations do not work with
> > triangle mesh objects.
> Sure they do. It's just not guaranteed to work everytime, but mostly
> it does work quite well.

:-}

Finite Patch Primitives

There are six totally thin, finite objects which have no well-defined inside.
They are bicubic patch, disc, smooth triangle, triangle, polygon and mesh.
They may be combined in CSG union but cannot be use in other types of CSG
(or inside a clipped_by statement). 

-- 
Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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My main concern is the best way to cut out a 'hole' from a an object, and
replace that hole with a window that is flush with original object.

In other words, lets say I have a cube, a tall thin one, and I want to make
a bunch of glass windows.  First I would do a CSG difference operation on it
using a bunch of smaller cubes to cut the holes.  Then I would use the same
tall thin cube with the smaller ones and do an intersection and use the
appropriate texture.  Then a 3rd CSG would combine the above 2 CSGs. I now
realize that this is more of a general POV CSG question than Moray.  But my
question still holds - is this the best way?

In the POV script I could do (with out textures):

#declare Building = box{<0,0,0><1,1,1> scale <tall,thin,1>}
#declare BunchOfCubes = boxes
then
union{
 difference{Building
            BunchOfCubes }
 intersection{Building
              BunchOfCubes {
}


Assume that Building is actually a mesh of triangles or a UDO object,
this is efficient because we are saving memory by referencing objects.
Is it possible to reference objects in Moray...  Now I'll go read the Moray
help...
--
Mike

wk: mik### [at] pyxiscom  www.pyxis.com
hm: mwe### [at] sciticom  www.geocities.com/mikepweber


"Ken" <tyl### [at] pacbellnet> wrote in message
news:38ED9DB2.37A7E2F6@pacbell.net...
>
>
> Lutz Kretzschmar wrote:
> >
> > Hi Ken, you recently wrote in moray.win:
> >
> > > I hate to burst everyones bubble here but CSG operations do not work
with
> > > triangle mesh objects.
> > Sure they do. It's just not guaranteed to work everytime, but mostly
> > it does work quite well.
>
> :-}
>
> Finite Patch Primitives
>
> There are six totally thin, finite objects which have no well-defined
inside.
> They are bicubic patch, disc, smooth triangle, triangle, polygon and mesh.
> They may be combined in CSG union but cannot be use in other types of CSG
> (or inside a clipped_by statement).
>
> --
> Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
> http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

Post a reply to this message

if you don't need to see into the windows, why don't you just make some
image maps to lay on the plane?

Mike Weber wrote:
> 
> My main concern is the best way to cut out a 'hole' from a an object, and
> replace that hole with a window that is flush with original object.
> 
> In other words, lets say I have a cube, a tall thin one, and I want to make
> a bunch of glass windows.  First I would do a CSG difference operation on it
> using a bunch of smaller cubes to cut the holes.  Then I would use the same
> tall thin cube with the smaller ones and do an intersection and use the
> appropriate texture.  Then a 3rd CSG would combine the above 2 CSGs. I now
> realize that this is more of a general POV CSG question than Moray.  But my
> question still holds - is this the best way?
> 
> In the POV script I could do (with out textures):
> 
> #declare Building = box{<0,0,0><1,1,1> scale <tall,thin,1>}
> #declare BunchOfCubes = boxes
> then
> union{
>  difference{Building
>             BunchOfCubes }
>  intersection{Building
>               BunchOfCubes {
> }
> 
> Assume that Building is actually a mesh of triangles or a UDO object,
> this is efficient because we are saving memory by referencing objects.
> Is it possible to reference objects in Moray...  Now I'll go read the Moray
> help...
> --
> Mike
> 
> wk: mik### [at] pyxiscom  www.pyxis.com
> hm: mwe### [at] sciticom  www.geocities.com/mikepweber
> 
> "Ken" <tyl### [at] pacbellnet> wrote in message
> news:38ED9DB2.37A7E2F6@pacbell.net...
> >
> >
> > Lutz Kretzschmar wrote:
> > >
> > > Hi Ken, you recently wrote in moray.win:
> > >
> > > > I hate to burst everyones bubble here but CSG operations do not work
> with
> > > > triangle mesh objects.
> > > Sure they do. It's just not guaranteed to work everytime, but mostly
> > > it does work quite well.
> >
> > :-}
> >
> > Finite Patch Primitives
> >
> > There are six totally thin, finite objects which have no well-defined
> inside.
> > They are bicubic patch, disc, smooth triangle, triangle, polygon and mesh.
> > They may be combined in CSG union but cannot be use in other types of CSG
> > (or inside a clipped_by statement).
> >
> > --
> > Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
> > http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

Post a reply to this message

Hi Ken, you recently wrote in moray.win:

> Finite Patch Primitives
> 
> There are six totally thin, finite objects which have no well-defined inside.
> They are bicubic patch, disc, smooth triangle, triangle, polygon and mesh.
> They may be combined in CSG union but cannot be use in other types of CSG
> (or inside a clipped_by statement). 
That's what the docs say, but not necessarily what the program does
:-)

You can take a triangle mesh and difference something out of it. It
may not look like you would expect, but it does make a hole.

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

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