DAN WHITEHOUSE
3D Artist
   
.

Nasir Al Molk Mosque

This page is just to show my experiments with different ways of lighting a scene with coloured shadows.
I think part of the problem is that this interior is only lit by the stained glass windows, there are no other light sources, and this presents a challenge.
Lighting by the usual methods is fine (as seen in the first image).

 

Different Lighting Set Ups:

01: Stationary lights. Directional light, Sky Light, a few spot lights to light the doors. Post Process volume. Settings are very high, as if for arch vis (0.5, 100, 20, 10, .75)
Basically a conventional lighting method. Probably the result I would expect, shadows and normal map details are crisp, but this method doesn't have Coloured Shadows.

 

02: Exactly the same settings as above on everything, except it uses a Static Directional Light. The reason being is that the windows have Coloured Translucent Shadows.
There is a second set of glass window meshes (hidden in game) that have a material on them that cast coloured shadows.
https://docs.unrealengine.com/en-us/Engine/Rendering/Materials/HowTo/ColoredTransluscentShadows

02b: Note the errors around the pillars:

 

03: Coloured Translucent Shadows. Different settings on lights and on the Post Process volume, but the shadows are still blurry and fuzzy.
The settings are very high, large light maps, and bake times take around 6 hours!

 

04: Spot Lights with light functions (3 spot lights each casting R,G or B. Set to dynamic)
No bounce from spot lights (or very little), the lighting is coming from the sky light.



05: Same as 04 above. Spot Lights with light functions (3 spot lights each casting R,G or B. Set to dynamic)
Spot lights aren't parallel, so the light is cast in a 'fan' shaed angle.

Reference Photos:

 

 

06: Stationary lights. Directional light, Sky Light, a few spot lights to light the doors. Post Process volume.
No Coloured shadows.

 

03b: Coloured Translucent Shadows. Different settings on lights and on the Post Process volume, but the shadows are still blurry and fuzzy.
The settings are very high, large light maps, and bake times take around 6 hours!