Indirect lighting is tricky for computers to simulate but essential for our eyes to recognize when observing a CG 3D environment that is attempting realism. Tom Sirdevan, look developer and lighting artist, provides an overview of what indirect lighting is and why it's traditionally difficult for real-time renderers to simulate.
- [Voiceover] Indirect lighting is any lighting contribution from light photons that have already interacted with a surface, which is a lot of photons to keep track of. And from a computer's perspective, this is very complex and difficult to calculate, but it's crucial to realistic lighting. Our eyes expect to see it, and things look immediately fake if we don't see it. So Unreal uses shortcuts or cheats to simulate the effects of indirect lighting. A nicer way of saying shortcuts or cheats is to say that Unreal employs rendering algorithms to do the job. Going forward, I'll be adding lighting features that are going to build upon each other in consecutive order throughout this chapter.
So if you're using the exercise files, you'll want to follow along from the beginning. Now let's go ahead and begin building our indirect lighting.
- Direct lighting
- Indirect lighting
- Creating a sky with Blueprint
- Deferred shading
- Dynamic sky and sun