Robert J Becraft <cas### [at] aolcom> wrote:

> I actually developed these trees very early.  I downloaded an animation off
> of AOL that was a walk through a forest.  The trees for that were cones on
> cylinders... I made them multi-cones on cone trunks with clear spots in the
> texture.  I've played with this texture for 4 years now... still haven't
> gotten something I like.

> The other problem is the rand function in POV is too regular.  If you create
> a set of random objects in a 50x50 area, and look at them from above, they
> come out looking like a 50x50 box with mostly evenly placed objects.  I'd
> like to have the objects truely randomly placed in the box such that some
> areas were denser than others, leaving clearings etc.

Actually, that would be *less* random, in a strict sense, but more natural.

> Haven't found a way to do this yet.  This would also help when generating
> tree-parts or vines for buildings in that the clear spaces would be openings
> in the branches or exposed wall sections.

> If anyone has a way to get this to happen in POV I'd surely like to have it.

I've got one.  I use a image map as a density pattern.  When I choose a
point, it looks up the density and has to meet the threshold with an
additional random number.  In addition, that random number determines the
tree size, if it is successful.  When a tree is added, the density is
lessened, meaning that the trees group, but big trees stifle growth around
them.  Gives very nice 'copsing' behavior.

An example image can be found at
http://darwin.cwru.edu/wedig/public_html/wgraphics/Leaves.jpg

It uses Gilles Trans' tree macro, and a really awful HF, but other than
that, looks pretty nice.

The code is not ready for prime time, but if you want it, I'd be willing to
send a copy, or post it to sf.

Geoff

Post a reply to this message