The light leaks are caused by incorrect shadow maps as has being discuss previously. Biggest issue is that Blender has poor default shadow values for interior scenes. See house scene leak fix below. Blender file HouseLightLeakFix.blend (2.5 MB)
This process should fix light leaks:
- Make sure that all walls have some thickness.
- To concentrate on fixing shadows and their problems. Disable “Screen Space Reflection” and “Free Lighting Cache”.
- To render nice smooth soft shadows under Sampling increase “Render Samples” to 256 or even 512.
- Under Shadow settings change:
“Method” to VSM.
Enable “High Bitdepth” and “Soft Shadows”.
Cube Size of 512px should be okay. Unless their is small size geometry or thin walls might need to increase to 1K or 2K. - Select the Light object the light type Point is working the best. Change the Shadow settings:
“Clip Start” change to 0.1.
“Softness” change to 0.
“Bias” change to 0.001.
“Exponent” can leave the default of 2.5.
“Bleed Bias” to 0.1. - Enable “Contact Shadows”. Change this settings:
“Softness” change 5.0 except for sun light leave at 0.2.
All other setting can be left at the default values.
Sun light are more difficult than the other types of lights to control light leaks.
Here are additional settings when using a sun light:
- Make sure the sun it’s pointing towards your interior.
- Use Cascade Size of 1024 if needed increase it to 2048.
- Now change the Sun properties.
a. Sun radius size should be kept small a value 0.2m or the default setting of 0.1m is even better.
b. If their is still light leaks increase the “Bleed Bias” in steps 0.1 until the leaks are gone.
Another important note is while learning how to setup all the Eevve settings do a Cycles render to use as a comparision.
Below is the original interior scene with it Cycles and Eevee including irradiance and reflection probe.
Cycles:
Eevee with this Blender file:LightLeakFix_eevee_c.blend (1.8 MB)
Below is a good shadow testing scene with Cycles and Eevee including irradiance and reflection probe.
Cycles:
Eevee with this Blender file:ShadowTest_eevee_c.blend (3.8 MB)
The Cycles scene was render to 2048 samples it was taking over 5 and half minutes. The Eevee scence was render in less than 3 sec without noise and all the render settings in high quality.
Edited: 1/2/2019 added sun light notes.
Edited: 3/20/2019 added change to contact shadows.