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1 Nov 2024 05:23:34 EDT (-0400)
  CSG'ing a mesh2 (Message 1 to 6 of 6)  
From: Greg M  Johnson
Subject: CSG'ing a mesh2
Date: 25 Oct 2007 22:22:10
Message: <47214f52@news.povray.org>
I'm thinking about a project for constructing things out of mesh2's. I think
I'd like to cut the mesh2 with CSG.


Is this unadvised (specifically. why then?)?
thanks.


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From: Trevor G Quayle
Subject: Re: CSG'ing a mesh2
Date: 25 Oct 2007 23:05:00
Message: <web.47215882922d66a72ae8612c0@news.povray.org>
"Greg M. Johnson" <pte### [at] thecommononethatstartswithYcom> wrote:
> I'm thinking about a project for constructing things out of mesh2's. I think
> I'd like to cut the mesh2 with CSG.
>
>
> Is this unadvised (specifically. why then?)?
> thanks.

It is unadvised at times, because it can be very difficult to figure out
what is in and what is out and you may not get what you expect, especially
if your mesh isn't fully closed.  It is however possible, try adding an
inside_vector to your mesh.  Read about it in the docs for more info.

-tgq


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From: Bill Pragnell
Subject: Re: CSG'ing a mesh2
Date: 26 Oct 2007 07:00:00
Message: <web.4721c854922d66a7731f01d10@news.povray.org>
"Trevor G Quayle" <Tin### [at] hotmailcom> wrote:
> "Greg M. Johnson" <pte### [at] thecommononethatstartswithYcom> wrote:
> > I'm thinking about a project for constructing things out of mesh2's. I think
> > I'd like to cut the mesh2 with CSG.
> >
> >
> > Is this unadvised (specifically. why then?)?
> > thanks.
>
> It is unadvised at times, because it can be very difficult to figure out
> what is in and what is out and you may not get what you expect, especially
> if your mesh isn't fully closed.  It is however possible, try adding an
> inside_vector to your mesh.  Read about it in the docs for more info.

As long as you're confident that all your normals are pointing in/out
consistently, and that the mesh is fully closed, there should be no
problem. I've done it before. It can be fiddly if you're building a mesh by
hand.


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From: Alain
Subject: Re: CSG'ing a mesh2
Date: 26 Oct 2007 08:57:23
Message: <4721e433$1@news.povray.org>
Greg M. Johnson nous apporta ses lumieres en ce 2007/10/25 22:25:
> I'm thinking about a project for constructing things out of mesh2's. I think
> I'd like to cut the mesh2 with CSG.
> 
> 
> Is this unadvised (specifically. why then?)?
> thanks.
You can have a mesh/mesh2 in any union.
You can diference/intersect a primitive from a mesh.
A diference will make holes where the second object is, and an intersection will 
keep the part of the mesh that is inside the second object.
You can't diference a mesh FROM a primitive, at least most of the time. An 
intersection or diference of 2 meshes is likely to return nothing.

-- 
Alain
-------------------------------------------------
The tree of liberty must be refreshed from time to time with the blood of
patriots and tyrants.
Thomas Jefferson


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From: Warp
Subject: Re: CSG'ing a mesh2
Date: 26 Oct 2007 09:21:11
Message: <4721e9c7@news.povray.org>
Alain <ele### [at] netscapenet> wrote:
> You can diference/intersect a primitive from a mesh.
> A diference will make holes where the second object is, and an intersection will 
> keep the part of the mesh that is inside the second object.
> You can't diference a mesh FROM a primitive, at least most of the time. An 
> intersection or diference of 2 meshes is likely to return nothing.

  Most of that is wrong. Just read the documentation about inside_vector.

-- 
                                                          - Warp


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From: Bill Pragnell
Subject: Re: CSG'ing a mesh2
Date: 26 Oct 2007 10:50:00
Message: <web.4721fd5f922d66a7731f01d10@news.povray.org>
Alain <ele### [at] netscapenet> wrote:
> intersection or diference of 2 meshes is likely to return nothing.

I have done this, and it worked perfectly. You just need a well-behaved
mesh.


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