Some things I'm doing are a spaceship in CSG ... mostly because I wanted
rounded corners, so it's cylinders & slabs (box or prism, depending)... I
need a fair bit
of 3D trig to get the slabs into the right places, of course. (Well, I could
have
made the spaceship a cube, but I think that one is trademarked... ;))

I'm working on a fountain, implemented as a parabolic distribution of
sphere-elements in a big glob, apply water parameters. The parabola is
simple
enough, of course, this one has been mostly trial and error to get a jet
that
is nice and noisy but not so noisy that it becomes pure static. I'm thinking
that
the water that the jets are in might be best modeled as an isosurface. I'm
going
to try some experiments with surfaces that look like,
sin(pow(x - fountain_x[i],2) + pow(y - fountain_y[i],2)) * (1/(abs(pow(x -
fountain_x[i],2) + pow(y - fountain_y[i],2))

I think that's it... of course, I haven't tried it yet, and the formula
needs a ripple-point for each jets source and splashdown point... by the
time I'm done
the object will probably take a couple days to render. It takes about six
hours to render anti-aliased with just the jets and a cylinder of water
(though if the
'granite' fountain & plane weren't also reflective that might help...)

Sorry, got sidetracked there. Hrm.

Things I -don't- know how to do include rotating about an arbitrary line
(though it seems like I should be able to derive -a- formula, if not an
-efficient- formula, from what math I have at this point.

Maybe I should find a 2D formula for rotation about an arbitrary point and
work from that...) and...
hrm. I'm sure there are lots of things. I know the latter parts of the
isosurface tutorial page started making me dizzy. ;)

Future projects are movements for a car, some constraints that approximate
cloth... oh, I got a recursive fractal tree macro working today, so I need
to
naturalize that... mmm....

Of course, sooner or later I've got to figure out a modeller, because I'm
unlikely to find a simple isosurface formula for Marilyn Monroe's body, or
such... ;) Of course there -is- one, but the best way to find it is
probably to  model and do a curve fitting. With a bit of work, I could
probably model most of a human figure without leaving the text editor (I've
defined M-x povray-current-buffer ... ;)) but the human face is a very
particular thing. I think I could CSG or hand-mesh up a reasonable
'cartoon' head, but the real thing requires a lot of detail -just so- ...
okay, I don't -have- to touch a modeller, but if I don't my scenes will
suffer for it. If I ever complete a scene. Mostly I get distracted by
another project after making an object and never really compose a 'scene'
as such.

Hrm. Oh, and I don't -have- a good algebra book, or a good trig book... I do
have a good calculus book, at least, but I think that will only help with
animations (a vector integral should, if I can still do them and I set it up
properly, give me the correct location and direction for an object
following a mathematically defined path. Not that I've done a vector
integral since it was homework some years back, but...)

Oh, I also don't know how to do anything but the simplest polynomial curve
fitting, and I should probably learn (I know, in many cases pov can do it
for me, but... pov can rotate a point about the axis for me too, but I
don't think
the result of that operation is returned anywhere I can use it... anyway,
there
will be cases where I need to be able to do for myself what pov can do...)

I suspect this post of reading like late night babble, which it probably is,
but it might give a better idea why I think I need more math texts, or at
least what I've done with the math that I have... it probably won't
engender much more advice, but it might encourage people to be a little
more sympathetic when I post a scraggly tree or a simple fountain to
images... ;)

And tempting as isosurfaces are to experiment with, I think I'm for bed.
'night povers!

--Chris

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