From Simulated Area Lights to GI
In closing, let’s revisit the red-and-white room that should be familiar to you from previous tutorial chapters. As you remember, we used a total of six Area lights and one shadow casting light to simulate sunlight entering the room through the windows on one side with a slight blue hue. We then corrected the intense over exposure created by the six light sources using color mapping.
The final result can be loaded here:
You can try reducing the intensity of the light sources to achieve the same lighting effect without color mapping.
A more interesting question would be if we can use Global Illumination to simplify the setup.
Try taking a drastic step and delete all six light sources in the Object Manager, disable color mapping and replace the ,Flourescent_off’ material with the ,Flourescents_on’ material for the flourescent lights. If you render the image it will turn out very dark, which isn’t surprising (the flourescent lights don’t do much to illuminate the room because they aren’t used as light sources).
Add Global Illumination in the Render Settings and use the settings shown in the image below (since the Samples setting is set to Low, the result will look a bit cloudy; for the final render, the accuracy should be increased greatly - which will also increase render times accordingly).
Since Diffuse Depth is set to 4, the intense sunlight that is cast through the window can be reflected by the many red objects in the room, which in turn creates a warmer ambient lighting throughout the room.
We also have a second window, through which light with a very slight blue hue is cast. Here we can use the sky’s own light by setting the Physical Sky’s Intensity to 150%. The result can be seen here:
Now set the Physical Sky’s Sky and Sun tabs’ settings as shown below to fine-tune the scene’s lighting:
The final result can be seen here.
This file can be used for experimenting with lighting setups and Global Illumination …