"Jeremy M. Praay" <jer### [at] questsoftwarecom> wrote in message
news:40c0888e@news.povray.org...
> "Gilles Tran" <tra### [at] inapginrafr> wrote in message

> > - using high radiosity settings on multi-layered, semi-transparent
meshes
> > (such as hair) tend to darken them, sometimes turning the texture into
> pure
> > black. I never found a solution for this.

> Yes, I've come across that.  I thought it was something stupid that I was
> doing, but eventually my scenes get so complex that I have to turn down
> radiosity settings anyway.  Well, that, and I spend a lot of time doing
> outdoors scenes, which generally don't need much radiosity.

Me too, I'm doing some outdoor scenes on Mars and have some semi-decent
looking hair, and haven't run into this.  Then again, I'm using the defautl
radiosity settings from Moray.  It sounds like I've just been lucky.

> I really hope that at some point someone can address the "smooth triangle
> artifact" problem.  Now that I'm aware of it, I've noticed that it pops up
> all over the place in other people's images.

I ran into with my terrain meshes - I'm using a lot of height fields and
sometimes get black triangles.  My Mars landscapes aren't terribly
reflective, though, so I don't seem to have as much trouble as others have
had.  Will post some images eventually, although my tank tread image in
P.B.I was done with radiosity and height fields.

> As meshes become more and more
> prevalent in POV-Ray pictures (which seems to be the trend for many of
us),
> this issue will probably become more of an annoyance.

Right!

I'm using CSG on my height fields though, which I think might make it easier
to use bump maps at least with these, it's not a pure mesh.  From reading
the description of the problem from the link you gave, it sounds like the
problem could be fixed by an 'inside'.  Is that possible?

> To avoid problems that I've encountered with normals on CSG surfaces, I
> generally try to use iso-surfaces when I can.  At the risk of sounding
like
> a complete buffoon, I have to ask if anyone has ever tried converting
smooth
> triangle meshes to bi-cubic patches?  It would certainly take care of this
> problem, but my guess is that render times would go through the roof, and
it
> might produce some other problems as well.  But we've certainly seen
> utilities that do the opposite (e.g. hamapatch).  It's easy for me to deal
> in the theoretical, since I have very little idea of how this stuff
actually
> works.

Interesting idea - at least for Poser models, I'd like to actually use some
real displacment mapping, but of course that brings up the whole
'displacement mapping with ray tracer' flame thing.

Poser5 has some nice effects you can do with real displacement maps, instead
of bump maps.  I'd prefer to make use of this instead of actual bump maps
for larger displacements, but bump maps can be effective for small things
like pores and fine wrinkles, that really aren't 'displaced' much at normal
resolutions.

        == John ==

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