ACE3 adds a realistic depiction of the Vector 21 rangefinder to the game. Unlike other rangefinders, it doesn't just magically show you the range to your target, but in exchange allows you to do alot of things with it that the other choices in Arma do not offer. The Vector's functions include, but are not limited to:
- Sight the circle on the first object and tap <kbd>Tab ↹</kbd> while further holding <kbd>R</kbd>. The first measurement is confirmed ("1-P" = first point).
- Press and hold <kbd>Tab ↹</kbd> until the azimuth appears.
- Sight the circle on the first object and tap <kbd>R</kbd> while further holding <kbd>Tab ↹</kbd>. The first measurement is confirmed ("1-P" = first point).
- Sight the second object and release <kbd>Tab ↹</kbd>.
- Tap <kbd>Tab ↹</kbd> once then press and hold it until the azimuth appears.
- Sight the circle on the object and tap <kbd>R</kbd> while further holding <kbd>Tab ↹</kbd>. The first measurement is confirmed ("1-P" = first point).
- Sight the Fall of shot and release <kbd>Tab ↹</kbd>. The left digits display the left (`L`)/right (`r`) correction value in meter and the right digits display the longer (`A` = add)/shorter (`d` = drop) correction value in meter. If <kbd>R</kbd> is tapped the height correction values will be displayed (`UP` and `dn`).