This is a Modeler Lscript that measures the exact distance between 2 selected points. To use it, simply select 2 points in Modeler and run the script. This is way more accurate than using the Tape Measurer tool; there must be other Lscripts out there that do this, but I haven't found them...
I take no responsibility for any grief these Lscripts may cause you and make no warranty regarding their effectiveness.