#### 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

## Units of measurement

To begin this section, we want to first define measurement and what exactly we will measure in the context of Unreal Engine 4. In a general sense, the definition of measurement is determining the size, length, or the amount of something (such as distance), the length/width/height of an object, or the volume of a particular space. In the context of Unreal Engine 4, we will measure the lengths of each component of a 3D vector in the 3D space and the X, Y, and Z dimensions. For the 2D game world, we will measure the X and Y axes. In the real world, we can use the U.S. Standard and the European Standard units of measurement to measure distance.

In the U.S., we can use the standard of lengths that involve the use of inches (in), feet (ft), yards (yd), and miles, whereas in Europe, there is the standard of lengths in place that includes millimeters (mm), centimeters (cm), meters (m), and kilometer (km). For our convenience and as a point of reference, here are a set of conversion charts between the U.S. and the European units of measurements. For more conversions, refer to this free conversion website at http://converter.eu/length/.

The following table shows the U.S. Conversions:

 1 ft 12 in 1 in 0.0833333 ft 1 yd 3 ft 1 yd 36 in 1 Mile 1,760 yd 1 Mile 5,280 ft 1 Mile 63359.999 in

The following table shows the European Conversions:

 1 mm 0.1 cm 1 cm 10 mm 1 cm 0.0099999 m 1 m 100 cm 1 m 1000 mm 1 mm 0.000999999 m 1 km 1000000 mm 1 km 100000 cm 1 km 1000 m

The following table shows U.S. to European Conversions:

 1 in 25.4 mm 1 in 2.54 cm 1 in 0.0254 m 1 in 0.0000254 km 1 ft 304.8 mm 1 ft 30.48 cm 1 ft 0.3048 m 1 ft 0.0003048 km 1 yd 914.4 mm 1 yd 91.44 cm 1 yd 0.9144 m 1 yd 0.0009144 km 1 Mile 1609344 mm 1 Mile 160934.4 cm 1 Mile 1609.3439999999998 m 1 Mile 1.609344 km

Now that we have a strong understanding of the real-world units of measurement, we are now ready to discuss how Unreal Engine 4 uses these units of measurement to determine distances and sizes of objects.