The Persistence of Vision Raytracer (POV-Ray).

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Attached to Project: POV-Ray
Opened by Jeff Wood - 2010-04-01
Last edited by Christoph Lipka - 2010-06-19

FS#92 - Sphere_Sweep Bug

This item may need to be merged with item FS#81. This is another sphere sweep bug, though they are of different spline types.

The code is

#include "colors.inc"

camera {
  location  <0, 0.0, -4.0>
  direction 1.5*z
  right     x*image_width/image_height
  look_at   <0.0, 0.0,  0.0>

light_source {
  <0, 0, 0>            // light's position (translated below)
  color rgb <1, 1, 1>  // light's color
  translate <-30, 30, -30>

#declare i_start = 0;
#declare i_stop = 3;
#declare i_step = 0.05;
#declare i_inc = i_start;
sphere_sweep {
  linear_spline                 // linear curve

  (i_stop - i_start)/i_step + 1,    // number of specified sphere positions
  #declare y_coor = 0.23*sin(7.1*i_inc);
  <i_inc, y_coor, 0>, 0.05
        #declare i_inc = i_inc + i_step;

pigment{color Orange}


Closed by  Christoph Lipka
Saturday, 19 June 2010, 01:13 GMT
Reason for closing:  Fixed
Additional comments about closing:  

No beta tester feedback for way over a month now; I consider that good news.

Jeff Wood commented on Thursday, 01 April 2010, 00:49 GMT

Sorry, posted wrong category. Also, did not know how to display image.

Christoph Lipka commented on Monday, 19 April 2010, 07:49 GMT

Under some circumstances (apparently when the camera is close to the plane perpendicular to the spline, and sufficiently far away), the coefficients of the quadratic polynom to solve grow seriously small, causing some approximation mechanism in the root solver to kick in where it’s not helpful.

The issue seems easy to fix, but I’m not sure yet whether to modify only the spline code or the root solver as such (the latter will obviously affect other geometry for good or for bad).

Christoph Lipka commented on Monday, 19 April 2010, 14:29 GMT

fixed with change #4944.


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