[Sorry] Re: Re: [Update REQ 6916]: polyhedra with holes in GeomView

[Geometry Center Software Development Group <software@geom.umn.edu>]

REQ 6916 is closed; must reopen it to assign someone.

... so the following mail message was not recorded:
From: Tamara Munzner <munzner at cs.stanford.edu>
Message-ID: <14349.40503.173057.89919 at weevil.Stanford.EDU>
Date: Wed, 20 Oct 1999 03:49:27 -0700 (PDT)
To: software@geom.umn.edu
Subject: Re: [Update REQ 6916]: polyhedra with holes in GeomView


> Is there any possibility that a future version of geomview would include
> such a capability?

Geomview is not under current development, so no, it's not very likely 
at all. Sorry.

> I can see now that my previous message was not clear.
> However, you've guessed it right. What I want to display would be for example,
> a cube with a through hole.

So you can't construct a cube with a hole in it that has only six
polygonal faces with holes. You'd need more. For instance, a working
convex decomposition of a single face would be this:

OFF 
8 4 0 
        1.632993 0.000000 1.0 
        0.000000 1.632993 1.0 
        -1.632993 0.000000 1.0 
        0.000000 -1.632993 1.0 
        .5  0.0 1.0 
        0.0 .5  1.0 
        -.5 0.0  1.0 
        0.0 -.5 1.0 
 
4       0 4 5 1 
4       1 5 6 2 
4       2 6 7 3 
4       3 7 4 0 
 

And a working non-convex decomposition would be

{appearance {+concave}
OFF
8 2 0
	1.632993 0.000000 1.0
	0.000000 1.632993 1.0
	-1.632993 0.000000 1.0
	0.000000 -1.632993 1.0
	.5  0.0 1.0
	0.0 .5  1.0
	-.5 0.0  1.0
	0.0 -.5 1.0

8	0 4 5 6 7 3 2 1
4	3 7 4 0
}

But you can't do something like this:

{appearance {+concave}
OFF
8 1 0
	1.632993 0.000000 1.0
	0.000000 1.632993 1.0
	-1.632993 0.000000 1.0
	0.000000 -1.632993 1.0
	.5  0.0 1.0
	0.0 .5  1.0
	-.5 0.0  1.0
	0.0 -.5 1.0

12	0 4 5 6 7 3 2 1 3 7 4 0
}

since it doesn't work properly.

Good luck,
Tamara