I've been doing tons of refining to get some awesome renders with POV-Ray (LDD, LDD to POV-Ray) but I have one remaining issue. I'm currently using the Custom HQ Radiosity default from LDD to POV-Ray as this has given me the best-looking result. It's pretty slow but it does a really good job.

What I'm encountering now are "artifacts" or something in some of the shadows. I'm going to continue trying to figure this out but if anyone has any suggestions I'm happy to hear them. The general gist of what I'm rendering is a white sky sphere, no base plane, and three area lights (one pointing down, two pointing at the front). Thanks!

Here's the result: http://imgur.com/a/6mmxC

Here are the settings:

    radiosity {
      pretrace_start 0.08
      pretrace_end 0.005
      count 1600
      nearest_count 20
      error_bound 0.02
      recursion_limit 1
      low_error_factor 0.25
      gray_threshold 0
      minimum_reuse 0.015
      brightness 1.0
      adc_bailout 0.01/2
      normal on
      media off
    }

 

Try lowering pretrace_end.

Values have to be tweaked according to the model (e.g. an all white model needs lower value than a darker one).

I generally use 4/image_width for pretrace_end (~0.0005 for 1920x1080) but can lower it to 1/image_width (~0.000125) with an all white, shiny model. (pretrace_start of 64/image_width; but my count is at 800 only and other values differ from yours.) I started from Povray’s predefined settings but finding the right values is difficult and tweaking the wrong one may greatly increase rendering time without real difference in the results.

Wow I lowered it from 0.005 to 0.001. It's taking significantly longer to render but on a small portion the results look really good.

I tried increasing error_bound last night. It helped but the overall realism in the shadows along corners dropped as well. Your approach works well. Do you mind sharing your entire radiosity setup? I'd like to give it a try and just see what it looks like.

Sure, should have done that first. Here it’s:

  radiosity {
    pretrace_start 64/image_width  // 64/image_width
    pretrace_end 4/image_width     // 4/image_width
    count 800                      // 800
    nearest_count 20               // 20
    error_bound 0.2                // 0.2
    recursion_limit 1              // 1
    low_error_factor 0.7           // 0.7
    gray_threshold 0               // 0
    minimum_reuse 0.005            // 0.005
    brightness 1.0                 // 1.0
    adc_bailout 0.01/2             // 0.01/2
    normal on
    media on
  }

(I keep “default” values in comments to remember where I started when I tweak them  )

It’s almost Radiosity_Final, with nearest_count increased and pretrace_* adjusted to image_width (as per comments in Povray’s doc). I assumed Povray’s defaults were tuned to 800x600 (pretrace_start of 0.08 for 800 = 64/image_width).

One day (or rather, one month), I may try to better fine tune it to speed it up….

Thanks! I'll try those settings next and see what I get. I was using radiosity_final for a while but it wasn't all that great for me.

Here's how things are looking: http://imgur.com/a/6uRbx. As long as the rest of the model looks good I think these settings should be good enough for my needs. :)

Hi,

Just getting started with Pov-Ray, this thread has helped but I was wondering if there is a good basic default that works with most designs that I can use as a starting point and change from there? Or use one most of my designs?