In article <3f1069e2$1@news.povray.org>,
 "Greg M. Johnson" <gregj;-)565### [at] aolcom> wrote:

> Right now, I'm trying to figure out which renders & parses faster:
> 1) a bicubic patch
> 2) a really dense triangle mesh of the same object (Hamapatch export to
> DXF).

Answer: it depends. The patch can precompute a lot of data, making 
memory and speed about equal to mesh. That precomputation takes parse 
time, bringing it closer to that of a high res mesh. How close? I don't 
know, and it probably depends on what settings you use.


> For example, I know making everything out of isosurfaces would be really
> slow.   I'm assuming "modelled"  laboratory equipment then exported to
> triangles would render much faster than asking povray to do the complex CSG.

> One could make a complex object using boxes & cylinders in povray with
> dozens of CSG statements.  I'm assuming for render time, using a formal
> modelling program like Moray, POVLAB, or Hamapatch should win hands down in
> terms of render time.  Am I correct.

No. You're asking POV to replace a relatively simple boolean operation 
on a group of primitives with a search through a much larger group of 
triangles.
For some cases it could be correct, but for others it is not. Boxes, 
spheres, and cylinders are all quite fast, you would have to get a 
pretty complex CSG before a mesh equivalent would be faster. If you're 
using a complex and slow isosurface or a sweep of thousands of spheres, 
a precomputed mesh becomes a better option. Of course, the mesh will be 
much slower to parse.

You're most likely "prematurely optimizing". You should look for a 
faster way if it is too slow, but scenes are usually slow for reasons 
other than CSG and data parsing.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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