Philippe Debar wrote:
> 
> Wild idea form someone who does not know much about all this - I:
> Is the order in which the vertices are written always the same relative to
> the direction of the normals? Paraphrase: looking always from the same side
> of the mesh (inside/outside), are the vertices always written in clockwise /
> anticlockwise order? I think some file formats / programs use this order to
> determine inside/outside.
> I do not know if this helps, but I hope it does

Aha... this is a possibility I'll have to try. I wasn't aware
that this might make a difference, but if it does, it's possible
it could in fact be the problem. I use a rectagular strip of
test points that get output if valid triangles are found, and 
not being aware the order would matter, made no special effort
to put them in any particular arrangement at output time. I
just confirmed the normals are being recomputed "for" me, because
the normals that got output from a converted RAW file didn't
match up with the ones supplied in the source file.

So.. if the converters/modllers are throwing out my normals and 
computing their own based on the order of the point output... 
well, it's easy to see how that might create the problem I'm 
seeing. I haven't got a lot of time this evening, but it looks 
like tommorow I've got a new set of experiments to run.

Thanks!
Charles

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Peter Popov wrote:
> I can't help you much on the other issues but have you tried this in
> Rhino?
> 
> Render -> Options -> Render Tab -> Backface checkbox

Oh, that's ok, Peter. Rhino is the one package so far that is 
presenting the test object the way I expected so no mods needed
there :)
 
> As of fixing the normals, try exporting to non-smoothed triangles and
> give the John's SSS (Surface Subdivision Suite) a try.

Hmm... yes, I ought to try combining some low res scans with a
little VanSickle magic to see what happens. Although, if the
converters and modellers are throwing out my normals, I'll
still have to overcome that problem separately, but Phillipe
just gave me a new angle to try there, so (crosses his fingers)
maybe I'll actually figure this out yet! :/

Thanks
Charles

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