What is Unreal?

Put simply, Unreal Engine is a game engine. There are many other game engines out there, but Unreal Engine is one of two that are the leading ones in the field of game development, the other being Unity. Had the people of Unity come up with MetaHumans, this book would have a slightly different title!

Unreal Engine is an incredibly powerful tool used for displaying graphics in real time. It was originally built for a PC-based first-person shooter game called Unreal and developed by Epic Games in the mid to late 1990s. In its earlier years, Unreal Engine was capable of rendering frames at rates as high as 60 fps on the CPU, giving the user a real-time experience.

However, there were many limitations, such as the frame size, limits on how many triangles could be displayed at any given time, and the complexity of the math behind the lighting. The end results were graphics that were not photorealistic but were a significant improvement on other game engines.

As GPUs improved over time, so did Unreal, as it was able to migrate a lot of its mathematical computations over to the GPU. As a result, the engine was able to rely on hardware that was specifically designed to calculate 3D rendering faster, and many features were developed to introduce photorealistic lighting solutions that were previously only available on traditional CPU path-traced solutions found in film and TV.

Path-traced or ray-traced rendering solutions involved very complex mathematics that would trace photons from the pixel of the final render through the CGI camera and around the scene. This tracing was incredibly time-consuming and required a lot of processing power just to deliver a single image. Therefore, conveying a sense of motion or real time was impossible for photorealism.

Because of very recent innovations, Unreal Engine is now being used to generate photorealistic renders in real time and we can see the result of that in Disney’s The Mandalorian. The company behind the real-time environments, StageCraft Industrial and Light & Magic, worked together to create LED backgrounds that displayed the output of scenes within Unreal Engine. In addition to supplying a photorealistic background, the LED backgrounds would also light the real actors, adding even more realism.

I expect that if you are a complete newbie to all of this, you may be scratching your head thinking: What does a game engine like Unreal do? More generally, it is a software application designed for building games that render graphics in real time. For games, Unreal is used for the creation of the following:

• User functions
• Game logic
• Environment design
• Animation
• Real-time rendering of what the user sees

Be it input from a mouse click, an Xbox controller button, or an Oculus headset, this user input affects how and when characters move and what is being displayed at any given time.

Ultimately, this book is about getting you up and running with your own characters and animating them how you want them to be animated even if you don’t have an art background or character animation background. Exciting stuff? I think so.

Next, let’s think a little more about how we are going to create those characters.