Op 6-12-2022 om 10:03 schreef Adrien:
> Hi,
> 
> I'm trying to use Povray to plot a surface defined by a polynomial equation
> spitted out by an auxiliary program. However, whenever the degree of that
> polynomial is 10 or more I get a bunch of artifacts/black dots. Is there a way
> to fix that ? Either directly in Povray, or in the auxiliary program ?
> 

wrapping up my experiments, I think I got a acceptable solution for your 
problem. Use the following additions/changes to your code (see attached 
image):

//=====================================================
//+w640 +h640 +am3 +a0.01 +ac0.99 +r3 +bm2 +bs8

#version 3.8;

global_settings {
   assumed_gamma 1.0
   radiosity {
     pretrace_start 16/max(image_width,image_height)
     pretrace_end   4/max(image_width,image_height)
     minimum_reuse  4/(max(image_width,image_height)-0.05)
     #if (Stochastic)
       count 10
     #else
       count 50, 1000
     #end
     nearest_count 20, 3
     error_bound 1
     recursion_limit 2
     low_error_factor .3
     gray_threshold 0.0
     //minimum_reuse 0.015
     maximum_reuse 0.1
     brightness 1

     adc_bailout 0.01/2
     normal off
     media off
     always_sample off
     //max_sample 1.0
   }
}

light_source {
   2*<5, 10, -40>
   color White
   area_light <5, 0, 0>, <0, 0, 5>, 5, 5
   adaptive 2
   area_illumination on
   jitter
   circular
   orient
   /*fade_power 1
   fade_distance 30*/
}
//=====================================================

All the rest is unchanged. Whether radiosity is "necessary" here is a 
matter of taste.

Very interesting poly btw...

-- 
Thomas

Post a reply to this message

Attachments:
Download 'adrien_poly.png' (176 KB)

Preview of image 'adrien_poly.png'