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 CAD / Ray-Tracing / 2897
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Subject: 
Re: New POV-Ray Edge Tracing Utility
Newsgroups: 
lugnet.cad.ray
Date: 
Tue, 24 Jun 2008 03:10:27 GMT
Viewed: 
10748 times
  
In lugnet.cad.ray, Travis Cobbs wrote:
(Note that I don't know enough about POV CSG to
know if gaps are a problem or not.)

Here's a quote from the POV-Ray documentation:

"Triangle mesh objects (mesh and mesh2) can now be used in CSG objects such as
difference and intersect, because, after adding inside_vector, they do have a
defined 'inside'. This will only work for well-behaved meshes, which are
completely closed volumes. If meshes have any holes in them, this might work,
but the results are not guaranteed.

"To determine if a point is inside a triangle mesh, POV-Ray shoots a ray from
the point in some arbitrary direction. If this vector intersects an odd number
of triangles, the point is inside the mesh. If it intersects an even number of
triangles, the point is outside of the mesh. You can specify the direction of
this vector. For example, to use +z as the direction, you would add the
following line to the triangle mesh description (following all other mesh data,
but before the object modifiers).

  inside_vector <0, 0, 1>

"This change does not have any effect on unions of triangles... these will still
be always hollow."

-Mike



Message is in Reply To:
  Re: New POV-Ray Edge Tracing Utility
 
(...) It certainly COULD be modified. However, it's up to Lars whether or not this actually happens. I looked at the mesh2 syntax, and changing to using it wouldn't really be trivial (although it probably wouldn't be all that difficult). Bear in (...) (16 years ago, 18-Jun-08, to lugnet.cad.ray)

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