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- POV-Ray Tutorial
Loops in POV-Ray
1. For + While
Comparison
2. Linear
Transformations
3. Circular
Transformations
>4. Moebius etc.
5. Screws
& Spirals
6. Twisting
Spirals
7. Snails
& Ammonites
8. Spherical Spirals 1
9. Spherical Spirals 2
10. Fibonacci Spirals
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Loops and Moebius and Similar Things
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If we use for double rotation a stick instead of a sphere as the basic element
and reduce the number of inner rotations to 0.5 we get as so called Moebius strip
- this kind of tape has only on side:
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//------------------------------------
#declare P_R =0.1; #declare P_H =0.75;
#declare Profile =
union{
sphere {<0, P_H,0>,P_R }
cylinder{<0,-P_H,0>,<0,P_H,0>,P_R}
sphere {<0,-P_H,0>,P_R }
texture{
pigment{color rgb<0.65,0.35,0.85>}
finish {phong 1}}
} //----------------------------------
#declare Radius_major = 3.00;
#declare N_major = 0.5;
#declare N_minor = 2500;
//------------------------------------
#declare Nr=0; // start
#declare EndNr=N_major*N_minor;// end
#while (Nr< EndNr)
object{Profile
rotate<0,0,Nr*360/N_minor>
translate<Radius_major,0,0>
rotate<0,Nr*360/EndNr,0>}
#declare Nr = Nr + 1; //next Nr_minor
#end // --------------- end of loop -- |
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If we change the number
of the inner rotations to 2.5,
we will see the following:
//----------------------------------
#declare N_major = 2.5;
//---------------------------------- |
In the case of integer numbers of inner rotations we are getting tapes with 2 surfaces,
in the case of 0.5 , 1.5, 2.5 etc. inner rotations we will get a tape with only one side.
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//---------------------------------
#declare P_R = 0.2;
#declare P_H = 0.65;
#declare Profile =
union{
sphere {<0, P_H,0>,P_R }
cylinder{<0,-P_H,0>,<0,P_H,0>,P_R}
cylinder{<0,-P_H,0>,<0,P_H,0>,P_R
translate<0.01,0,0>
texture{pigment{color rgb<1,.65,0>}
finish {phong 1}}}
sphere {<0,-P_H,0>,P_R }
texture{pigment{color
rgb<1,0.3,0.7>}
finish {phong 1}}}
//---------------------------------
#declare N_major = 4;
//--------------------------------- |
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