Swinging Spiral Pendulum

About oscillations of spirals in sine rythm.

Swinging Spiral Pendulum:
For the construction of a spiral pendulum we need to calculate its actual length.
First we define the minimal length and the amplitude of the spiral. With this values we calculate the medium length:

#declare Amplitude = 0.60;
#declare Minimal_Length   = 0.80;
#declare Middle_Length    = Amplitude + Minimal_Length;

//---------------------------------------------- time ----------------------
#declare Time_test = 0.25; // 0.25/0.75 shows maximum/minimal extension!!!

#declare Spiral_Length = Middle_Length+Amplitude*sin((clock+Time_test)*2*pi);
//------------------------------------------------------ ------------------- 

scene description for POV-Ray:
"spiral0.ini" and
"spiral0.pov"

The Spiral made with a While Loop:

#declare Spiral = //--------------------------------- the spiral union{ #local N_per_Rev = 500; // Number of Elements per revolution #local N_of_Rev = 8.00; // Total number of revolutions #local H_per_Ref = Sp_Length / N_of_Rev;// Height per revolution #local Nr = 0; // start loop #while (Nr< N_per_Rev*N_of_Rev) sphere{ <0,0,0>,0.025 translate<0.25, -Nr*H_per_Ref/N_per_Rev, 0> rotate<0, Nr * 360/N_per_Rev,0/gt; texture{ Chrome_Metal finish {diffuse 0.9 phong 1}} } #local Nr = Nr + 1; // next Nr #end // --------------------------------- end of loop sphere {<0,0,0>, 0.4 translate<0,-Nr*H_per_Ref/N_per_Rev-0.2,0> texture{ pigment{color rgb<1,0.65,0>} finish {diffuse 0.9 phong 1}} } } // end of union -------------------------------- end of spiral object { Spiral translate< 0.0,2.42,0>} //------------------------------------------------

Some examples for animations of this kind
you can find here: 3D-Animations - Oscillations .