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Subject: 
Re: Need help with errors and how to make renders look like this?
Newsgroups: 
lugnet.cad.ray
Date: 
Mon, 2 Jan 2006 06:51:27 GMT
Viewed: 
8783 times
  
I've been working on and off on a tutorial on how to render LDraw files
with radiosity and HDRI for a whole while now, but real life keeps in
intruding... I promise I'll try to finish it and get it (and all my
include
files) online before the end of the year!

BTW, I've done a quick test render of the Enzo. You can find it at
http://www.brickshelf.com/gallery/Koyan/Temp/Misc/8652.png

Cheers,
Koyan

Hi Koyan, I have made an attempt to try HDRI lighting and I am not sure if I
am doing things correctly or not. Could you look over what I am doing and
let me know if I am doing anything wrong? Here is what I have done so far:

(1) Installed POV-Ray 3.6
(2) Downloaded Mega-POV 1.2.1. I then extracted it over my POV-Ray 3.6
installation.
(3) Run mpengine.exe from the POV bin folder.
(4) Made sure my .pov file had the following at the top:

#version unofficial MegaPOV 1.21;  // version number may be different

(5) After the #declare DIF = 1.0; statement I did menu option
INSERT->SPECIAL EFFECTS->RADIOSITY which inserted the following code:

// radiosity (global illumination) settings
global_settings {
  radiosity {
    pretrace_start 0.08           // start pretrace at this size
    pretrace_end   0.04           // end pretrace at this size
    count 35                      // higher -> higher quality (1..1600) [35]
    nearest_count 5               // higher -> higher quality (1..10) [5]
    error_bound 1.8               // higher -> smoother, less accurate [1.8]
    recursion_limit 3             // how much interreflections are
calculated (1..5+) [3]
    low_error_factor .5           // reduce error_bound during last pretrace
step
    gray_threshold 0.0            // increase for weakening colors (0..1)
[0]
    minimum_reuse 0.015           // reuse of old radiosity samples [0.015]
    brightness 1                  // brightness of radiosity effects (0..1)
[1]

    adc_bailout 0.01/2
    //normal on                   // take surface normals into account [off]
    //media on                    // take media into account [off]
    //save_file "file_name"       // save radiosity data
    //load_file "file_name"       // load saved radiosity data
    //always_sample off           // turn sampling in final trace off [on]
    //max_sample 1.0              // maximum brightness of samples
  }
}

(6) I then replaced my lights statement with the following HDRI sphere:

// Create an infinite sphere around scene and allow any pigment on it
sky_sphere {
        pigment { image_map { hdr "stpeters_probe.hdr" once interpolate 2
map_type 7 } }
}

I am not super happy with the lighting results. I know it is partly
dependent on the HDRI image used but I am not sure if my poor results are
due to not a great HDRI image, poor radiosity settings (I am using the
default settings inserted), or a combination of both. My images render very
quickly (about 45 seconds) at 640x480 AA 0.3 so I am sure I am doing
something wrong. Most good looking images take a long time to render.

Would it be possible for you to provide a sample .pov file (with associated
include files if you have any) along with a sample HDRI image? I am sure I
could learn a lot by just looking at your settings and the HDRI image you
used.

Best Regards,
John



Message is in Reply To:
  Re: Need help with errors and how to make renders look like this?
 
Hi John, Orion's already explained most of how I work as well: L3P the .mpd with LGEO and mesh-enhance it. (I never just run the whole file through the enhancer, just certain parts here and there.) Add in radiosity and the lugnet colors. (I'm using (...) (19 years ago, 26-Dec-05, to lugnet.cad.ray)

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