Support Forum

Why is light enteri...

Why is light entering fully enclosed spaces in my model?  



My results seem off.

1 Answer

This is typically due to the way radiance calculates ambient light (i.e. light that bounces off of surfaces, rather than emanating from a light source like the sky).


You can likely solve this issue by:

  • Separating illumination grids into spaces, not allowing them to pass through walls.
  • Modeling walls with thickness, rather than thin planes
  • Making sure values for materials are reasonable (e.g. reflectance <100%).


If the issue persists, adjust Radiance parameter settings (click “Show Quality Details” under the “Quality Settings” drop-down menu) as follows:

  • Decrease ambient accuracy (-aa; but keep it above 0)
  • Increase ambient resolution (-ar)
  • Increase ambient divisions (-ad; typically in multiples of 2)
  • If all else fails, you can set -aa = 0, but you must also set the limit weight (-lw) to something very small (typically approx. 0.0000001). You can continue to increase -ar and -ad until you achieve the desired accuracy.


More details:

The Radiance parameters -aa, -ar, and -ad, combined with the size of the scene (listed alongside Radiance parameters in the quality details drop-down), determine the minimum ambient spatial scale. If this value is larger than your wall thickness or grid point spacing, ambient light can “leak” between points.

This post was modified 5 months ago by LightStanza