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Paul Bourke posted this in c.g.r.r today:
http://www.swin.edu.au/astronomy/pbourke/modelling/spring/
I fed the parametric function into MegaPov, but I'm not completely happy
with it. On the page Paul says: "It is a parametric equation in terms of
parameters u and v. Both range from 0 to 2 pi, increasing u will give
multiple windings."
When I use <0,2*pi>,<0,2*pi> for the uv boundaries, the scene stays black.
Can somebody explain me this and what the uv boudary exactly is?
//===scene
#version unofficial MegaPov 0.6;
global_settings {assumed_gamma 1.0}
light_source {<500,500,-500> rgb 1}
camera {location <0,0,-5> look_at <0,0,0>}
#declare r1 = 0.5;
#declare r2 = 0.5;
#declare periodlength=1.5;
parametric {
function
r2 * (sin(v) + (periodlength * u / pi)),
(1 - (r1 * cos(v))) * cos(u),
(1 - (r1 * cos(v))) * sin(u)
<-2*pi,-2*pi>,<2*pi,2*pi> //<0,2*pi>,<0,2*pi>
<-2,-1.5,-1.5>,<2,1.5,1.5>
accuracy 0.01
precompute 20,[x,y,z]
pigment {rgb 1}
}
//===end scene
Ingo
--
Photography: http://members.home.nl/ingoogni/
Pov-Ray : http://members.home.nl/seed7/
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In article <8FE### [at] povrayorg>, ing### [at] homenl (ingo) wrote:
> When I use <0,2*pi>,<0,2*pi> for the uv boundaries, the scene stays
> black.
This is the same as saying:
u = from 0 to 0
v = from 2*pi to 2*pi
I think you want to use <0, 0>, < 2*pi, 2*pi>.
--
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/
<><
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Chris Huff wrote:
>This is the same as saying:
>u = from 0 to 0
>v = from 2*pi to 2*pi
>
Ah, this makes sense and I can' read :(
Is precompute limited to 20? At 21 it POV says "Precompute: invalid depth"
.
Thanks Chris,
Ingo
--
Photography: http://members.home.nl/ingoogni/
Pov-Ray : http://members.home.nl/seed7/
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In article <8FE### [at] povrayorg>, ing### [at] homenl (ingo) wrote:
> Is precompute limited to 20? At 21 it POV says "Precompute: invalid
> depth"
It can not be less than 1 or more than 20. Why? I have no idea...I don't
even really know what it does.
--
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/
<><
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