A PHYSICSMATERIAL2D file is a data asset file used by Unity, a development platform for developing 2D and 3D games. It contains information that describes the friction and bounce physics between 2D objects when they collide in a game. PHYSICSMATERIAL2D files are saved in YAML (YAML Ain't Markup Language) format, which is a human-readable data format.

PHYSICSMATERIAL2D file open in Microsoft Notepad You will most likely only encounter PHYSICSMATERIAL2D files if you are a game developer building a game with Unity. The information in the file dictates the friction and bounciness of a material. For example, if you wanted to create a bouncy object, you would set the "bounciness" value to be a high number (0 is no bounce, while 1 is a perfect bounce with no lost momentum). You can open and modify a PHYSICSMATERIAL2D file with Unity Editor, which is included with Unity. To create a PHYSICSMATERIAL2D file with Unity, right-click the files area in the window, and select Create → Physics Material 2D.