Allegro PCB Design Tutorial
Show etch length while routing
In many cases you need to display the length of the routed trace as you go along. If you need to know just the length of the segment you are routing, you need to just give the command
etch length
It will pop up a window showing the length of the routed segment. This video shows the action.
In many cases you want to always display the total routed length as you are routing. To do this you need to set a Go to Setup -> User Preferences -> Route -> Connect -> and check the allegro_etch_length_on
Now any time you route, it will show the length of the trace routed.
This youtube captures the complete sequence.