Apply scale for the custom unit in the ruler

You can define here a scale which will be applied for this custom unit in the ruler. This scaling enables you to view a measure of the drawing in a natural way as it was intended by the drawing creator. Many of the architectural, construction, engineering, surveyor etc. drawings has its own natural unit and scaling. For example you can have a surveyor plan whose natural unit is km (kilometer) and scale is 1:20000. Then using the custom unit with a corresponding scale will allow you to see the measure in the ruler in the proper way.

You can apply the scale either as ratio or as parity. For example if the drawing scale is indicated as 1:1000, then it is ratio. If the drawing scale is indicated as 1 cm =  2 m, then it is parity.