Constant Physical Size

When a Canvas has the UI Scale Mode set to Constant Physical Size, every item in the UI will maintain its original physical size, regardless of the size of the screen. Physical size is referencing the size it would appear to the user if they were to take out a ruler and measure it on their screen. Much like Constant Pixel Size, items on Canvases with this UI Scale Mode will not scale. If you had a UI item that you wanted to always be a specific width and height, you'd put it on a Canvas that has this UI Scale Mode. For example, if you wanted a button to always be 2 inches wide and 1 inch tall, you'd use this mode.

When you change the UI Scale Mode to Constant Physical Size, you will see the following properties appear within the inspector:

• Physical Unit: The unit of measure. You can select from Centimeters, Millimeters, Inches, Points, and Picas
• Fallback Screen DPI: If the DPI is unknown, this is the assumed DPI
• Default Sprite DPI: The DPI of all sprites with Pixels Per Unit that are equal to the Reference Pixels Per Unit