Tipster Tawfik Shehata shares a trick that allows you to update a distance from the drawing model in AutoCAD without using a measuring tool.
"The inquiry commands in AutoCAD, such as Distance and MeasureGeom (for distance, radius, and angle) are a quick method to obtain some measurements from your drawing, however you don't really need to use these tools if you are going to re-enter the values using the keyboard to perform a command within the same drawing.
"For example, if you want to offset a line to a distance similar to a distance between two existing lines in your model, then you don't need to measure this distance, memorize it, and then re-enter it in the Offset command. Instead, when the Offset command prompts you to specify a distance, simply move your cursor and pick a point on one of these two existing lines, then when prompted to specify the second point, go perpendicular on the other existing line, then continue the command as per usual.
"The same concept applies to other commands including Array, Fillet, Chamfer, Measure, and Pedit (when specifying new width). Also in the Scale and Rotate commands, you can use the Reference option to modify the selected objects using existing geometry in the model.
"In addition to saving time and eliminating data entry mistakes, this method is also independent from the drawing current precision, so if the required distance real value was 1.23456789 and the current precision was 0.00 and you used the keyboard entry, then the result will be 1.23 but if you used the method suggested here, then AutoCAD will use the 1.23456789 regardless of the current lower precision."
Notes from Cadalyst tip reviewer Brian Benton: This is a great way to save some time and reduce errors. Many AutoCAD commands will allow you to define a distance by picking points. You can find out which commands allow this input type by reading the prompts in the Command line during a command.