Hey folks...

I was trying to take the sample hdr_mapping.pov scene and use it as a 
base for my own HDR experiments.

So, I set up a quick scene with just a camera looking at a sphere using 
the generated map from hdr_environment. Looked good, nice smooth shading 
and lighting.

Then I swapped the pigment statements in the HDR sphere to the mapping 
type (7) that is supposed to work with Paul Devebecs spherical HDR maps. 
All the maps of his that I have tried have had very strange effects on 
the surfaces, almost like "light noise". Using the HDR file from the 
Rendering with Natural Light demo, you can see that the sphere is very 
spotty. Please see the attached picture for an example. I've also 
included a pic done with the "grace" probe. (yuck!)

Considering that all that is different between these scenes is the type 
of HDR, I can't figure out what is going on.

Has anybody else been able to succesfully get these types of maps to 
work correctly?

Thanks!

Arlo


// CODE:

#include "colors.inc"

#version unofficial MegaPov 1.10;

// radiosity (global illumination) settings
global_settings {
   max_trace_level 15
   radiosity {
     pretrace_start 0.08
     pretrace_end   0.01
     count 800
     //count 250
     nearest_count 8
     //nearest_count 5
     error_bound 0.07
     //error_bound 0.2
     recursion_limit 2
     brightness 1

     normal on
     randomize on
   }
}

camera
{
    location <0, 2, -3>
    look_at <0, 1, 0>
    angle 90
}

sphere
{
    <0, 0, 0>, 1
    translate <0, 1, 0>
    pigment
    {
       color White
    }
    finish
    {
       ambient 0
       diffuse 0.7
    }
}

box
{
    <-2, -0.1, -2>, <2, 0, 2>
    pigment
    {
       color White
    }
    finish
    {
       ambient 0
       diffuse 0.7
    }
}

sphere {
   0,200
   pigment { image_map { hdr "c:\grace_probe.hdr" once interpolate 2 
map_type 7 } }
   //pigment { image_map { hdr "c:\hdr_env.hdr" once interpolate 2 
map_type 1 } }
   finish { ambient 0.8 diffuse 0 }
   scale <-1,1,1>
   hollow
   rotate 120*y
}

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Preview of image 'isosurface.jpg'

Preview of image 'isosurface2.jpg'