POV-Ray : Newsgroups : povray.unofficial.patches : Why copying a CSG doesn't work as copying a mesh? : Re: Why copying a CSG doesn't work as copying a mesh? Server Time
2 Sep 2024 04:15:33 EDT (-0400)
  Re: Why copying a CSG doesn't work as copying a mesh?  
From: Nicolas Calimet
Date: 8 Oct 2000 11:47:04
Message: <39E098B5.32B4CA7A@free.fr>
> Try mesh2.  Mesh objects save memory by making vertex & edge lists.  This
> means that vertices are shared by adjacent triangles, so duplicates are
> removed.  This removal of duplicates can take some time during parsing.  The
> mesh2 object doesn't have to remove duplicates because it takes the edge and
> vertex as its parameters and does not need to construct them.  Mesh2 objects
> should parse very quickly.
> 
> -Nathan

	Yes, I know all of that, and I definitely stopped using the good-old-
original mesh object when the mesh2 appeared in MegaPOV 0.3 (but I'm still
waiting the Linux port of 0.6/0.6a to get the new fixes related to textures
interpolation).
	Just a thought... Duplicates removal should not be so long since the
data are stored using hash tables. I noticed in POV 3.1g code (but not yet
checked the MegaPOV code) that the degenerate triangles are tested several
times in different places, so this is not very efficient and may slow down
the parsing.
	Also I think the mesh2 object is much faster to parse because its
size is predefined at the beginning (not necessary to allocate/reallocate
memory all the time) and there are much less data to parse for exactly the
same information. I know these are the reason why you guys created it and
I wanted to thank you for integrating the good stuff in POV 3.5 !


*** Nicolas Calimet
*** http://pov4grasp.free.fr


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