"WaveMaster" <nos### [at] yahoocom> wrote:
> The following example of a 3D-fractal animation does not work as expected.
>
> The animation rotates a 3D-fractal around the y-axis. When you render the
> animation (25 fps), you will see a 3D-fractal, rotating around the Y-axis,
> but additionally you will see an inner move/flow of the fractal itself.
> This inner-move makes a jump in speed and direction when you reach a
> special position. This happens between frame 535 and frame 536 of an
> animation with 4000 frames.
> Between frame 535 and 536, the inner-move of the fractal is suddenly
> increased
> and the direction of the inner-move is reversed. Too see this effect, render
> an animation from frame 500 up to frame 560 with a resolution of at least
> 720x576 with Anti-Alias 0.3 on. (PovRay 3.6.1.c Windows version)
>
> How can I suppress/avoid this strange change in speed and direction of the
> inner move/flow of fractal ??
>
> Is there an error in the 3D-fractal calculation ??
>
>
> Full example:
>
> // Insert in povray.ini
> Initial_Frame = 1
> Final_Frame = 4000
> Cyclic_Animation = on
> Subset_Start_Frame= 500
> Subset_End_Frame=560
>
>
>
> #include "chars.inc"
> #include "colors.inc"
> #include "textures.inc"
> #include "shapes.inc"
> #include "shapes2.inc"
> #include "shapesq.inc"
> #include "stones.inc"
> #include "stones1.inc"
> #include "stones2.inc"
> #include "stars.inc"
> #include "skies.inc"
> #include "metals.inc"
>
> global_settings {
>   number_of_waves 10
>   assumed_gamma 1.0
>   max_trace_level 10
>   adc_bailout 0.006
>   max_intersections 80
>   photons {
>     count 40000
>     media 100
>     gather 30, 120
>     autostop 0
>     jitter .4
>   }
> }
>
> camera{
>   location <0, -66,-650> // position of camera <X Y Z>
>   sky y
>   up <0, 1, 0>           // which way is +up <X Y Z>
>   right <-1.77 0.0 0.0>  // which way is +right <X Y Z> and aspect ratio
>   look_at <0.0, 0, 0>    // point center of view at this point <X Y Z>
> }
>
> light_source{
>   <0,-66,-380>
>   color rgb 1.5
> }
>
> julia_fractal{
>   <-0.5664, 0.5106, 0.0224, -0.3024>

>   precision 50
>   max_iteration 38
>   quaternion
>   sqr
>   hollow on
>   texture {
>     pigment{
>       rgb <1,1.0,1.0>
>     }
>     finish {
>       ambient 0.05
>       metallic 0.4
>     }
>   }
>
>   rotate <-2,19,0>
>   rotate <0,0,-10>
>   scale <250, 250, 1000>
>
>   rotate<0,90+clock*360*1,0>
> }


To increase the precision does not solve the problem.

I suppose, when the camera position hits the shape of the fractal
(As soon as I am inside the fractal), the calculation of the fractal
data changes and the inner move also.

Why can I not see the Wheel-effect as long as I am outside the shape of
the fractal?? And why does the wheel-effect have an effect on the whole
fractal?
(the inner move/flow changes for the whole fractal)

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