The ** Measurement** tool is used to measure distances on the screen using a
Reference Length as its basis. The construction is the same as for a
Line Segment. If no

*Reference Length*has been constructed yet the

*Measurement*has no way of measuring the distance so the construction will be cancelled. Note that the measurement is accurate at the scale of its construction. If the

*Measurement*path is rescaled, the value will be no longer be valid. The only other option available when constructing a

*Measurement*is whether to use the same paint that was used for the

*Reference Length Segment*segment (the option is called

*“Unit Paint”*) or to use the currently selected painted (called

*“Current Paint”*). Here’s an example: