[Radiance-general] Plants, Landscaping, Entourage, and Radiance...]

[Rob Guglielmetti]

Mornin'.

> I'm still a Radiance noob,

Better than being a Radiance boob, which is what I feel like half the 
time.  =8-)

> What I'm wondering is how to deal with
> things such as landscaping, people, cars,...

> I'm concerned that modeling these items
> whole, and including them within the
> scene, will add too much complexity to
> the project and greatly increase
> rendering times on large exterior views.

Radiance can handle the complexity, (i.e. the massive amount of 
polygons), no problem.  What does happen is that the ambient 
calculation gets, as Greg likes to say, "nasty".  Of course, as for 
most limitations in Radiance, the author has developed a tool for 
dealing with that.  You can exclude materials from the ambient 
calculation.  By specifying -ae (material) in your rpict/rtrace command 
(or by placing it in your .rif file (render= -ae [material]) you tell 
Radiance to apply the ambient (-av) value to all materials on the -ae 
line, thus skipping a whole lot of interreflection calculations.

> Does everyone typically have these
> items as whole Radiance models, instanced
> into the 'scene'? Is this not a problem
> due to Radiance's render engine's differences
> from other 3D packages? What about the
> repetitiveness apparent in an image when
> the same tree/bush/person/car is used
> over and over and over again? I see
> some exterior renderings on Visarc's
> website that have wonderful looking
> trees, does anyone know how those
> were done?

Generally, yes, these complex "library" items are instanced.  This 
saves lots of memory.  I have also read about people who write scripts 
that randomize the placement of these library items.  By varying the 
tree instances over three or four distinct models, and further varying 
the scale & rotation of each instanced tree, you can create a very 
random look to your "forest", for example.  AFAIK, the trees you see in 
Visarc's renderings are all 3D geometry.  They pride themselves on 
creating everything and faking nothing.  Amazing, yeah?

-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-
   Rob Guglielmetti
rpg@rumblestrip.org
www.rumblestrip.org