With this method, you can use any object for which you have the height information available in the mm or inches unit. For example, you can use the ruler or any measure tap in a vertical direction. So Place any object on the screen according to the frame given below, keep in mind that you need to match any object border with the red lines. Click on the + and - buttons to adjust the slider until the red lines match your object's height. Once you are done just specify the height information that you have in the mm or inches units, in the input field provided below and be sure to select the mm or inches from the dropdown option.