POV-Ray : Newsgroups : povray.binaries.images : ivy on a tree WIP : ivy on a tree WIP Server Time
7 Aug 2024 17:26:23 EDT (-0400)
  ivy on a tree WIP  
From: Kenneth
Date: 19 Jan 2006 02:15:01
Message: <web.43cf3b13e1be95c0dbcfc3c90@news.povray.org>
Hi, all!

My first post at p.b.i.

A rather complex, multi-TRACE experiment, using #while loops of course, with
LOTS of conditional #if's and rand calls.  And, for the ivy leaves, that
magical Point_At_Trans macro, in transforms.inc.

I purposely didn't make use of any of the tree or hair-making macros
available (or look at their code), as I wanted to see what I could come up
with by myself.  The trial-and-error method!

The point of this was to create a wildly-curving object (the tree, an sPatch
model) and have the trace operations accurately follow its shape no matter
where.

Right now, the ivy isn't actually attached to the vines--but there are so
many leaves to hide that fact, *hopefully* it's not apparent.

Each vine is a union of short cylinders. (No "branching" yet.) I tried
sphere_sweeps for the vines, using the cubic_spline type, but the result
looked like I had sprayed the tree with Silly String. Too curvy. (I suppose
I could try another spline type, with more control points, and massage
their values, but it was difficult enough, code-wise, dealing with just a
cubic spline!) And sphere_sweeps take a *long* time to render. Besides, I
kind of like the sharper "angular" look of the cylinders. Oh, and I
purposely made the bottom of the vines come out of the ground and "reach"
for the tree--as if they are slowly, inexorably pulling the poor tree down
into Mother Earth. (On my to-do list is attaching ivy directly to those
cylinders.)

Hope you like it!

Ken


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