#### Overview of this book

This book gives readers practical insight into the mathematical and physics principles necessary to properly implement physics within Unreal Engine 4. Discover how to manipulate physics within Unreal Engine 4 by learning basic real-world mathematical and physics concepts that assist in the implementation of physics-based objects in your game world. Then, you'll be introduced to PhAT (Physics Asset Tool) within Unreal Engine 4 to learn more about developing game physics objects for your game world. Next, dive into Unreal Engine 4’s collision generation, physical materials, blueprints, constraints, and more to get hands-on experience with the tools provided by Epic to create real-world physics in Unreal Engine 4. Lastly, you will create a working Vehicle Blueprint that uses all the concepts covered in this book, as well as covering advanced physics-based topics.
Unreal Engine Physics Essentials
Credits
www.PacktPub.com
Preface
Physics Asset Tool
Constraints
Physics Damping, Friction, and Physics Bodies
Materials
Index

## What is an Unreal Unit?

Back in the days of the UDK or Unreal Engine 3, the units of measurement were based on what was called Unreal Units (uu), where one uu equaled 0.75 in, or 16 units equaled 1 ft. In Unreal Engine 4, the measurement has changed to where 1 uu is equal to 1 cm by default, but the engine allows you to change the conversion ratio between an Unreal Unit and a meter in its World settings, as shown in the following screenshot:

The value of `100.0` in this property equates an Unreal Unit to 1 cm. For example, by changing the World to Meters property to the value of 1 (as shown before), it will equate 1 uu to 1 m and a value of 1,000 will result in 1 uu equaling 1 mm. For the purposes of this project, we will leave the default value of 100 so that an Unreal Unit will equal 1 cm, but for future reference, this is the World settings property you would want to alter in order to change this conversion ratio.