Sight, Radar, Sonar and Jamming

Total Annihilation keeps track of what you can see on a grid of squares 32 across in the units used for ranges. Sight, radar and sonar each follow their own rules, and they matter in different ways when your units choose what to shoot.

Sight

A unit sees the squares within its sight distance, which is rounded to steps of 32. With the line-of-sight setting on True, the view is blocked by hills: the game draws lines out from the unit's eye height, and a square is seen only if no higher ground lies in between. With Circular or Permanent, a unit sees its whole circle.

Squares you have seen stay explored for the rest of the game, even after your units leave.

When one of your units is destroyed, its view stays open for 2 seconds after its death, so you may see what destroyed it even when no other unit is watching.

Radar and Sonar

Radar is updated once a second.

• A radar unit must be switched on. A Radar Tower that you switch off stops showing contacts.
• Radar finds units on land, on the water and in the air within its range. Sonar finds units under the water within its range.
• Units marked as stealthy never show on radar: the Hawk, the Vamp and the Resurrection Kbot.
• A cloaked unit still shows on radar, unless it is also stealthy.
• Radar, sonar and jammers keep working when your energy runs out. Their energy use is simply not paid.

A Radar Tower lists 5 energy of use and 5 energy of output. The output flows all the time, while the use is charged only when the tower is switched on. Switched on, it costs nothing overall.

Jamming

A jammer hides every unit within its jamming range from other players' radar. It does not check whose units they are, so it also hides enemy units that stand near it. A jammer belonging to an ally hides units from your radar too.

Jamming works against radar and sonar only. Any unit that one of your units can see is shown, jammer or not. This is why the 1997 manual says the Fink scout can still report enemies that use jammers.

What Your Units Can Shoot

Your units pick targets by themselves only among enemies that you can see. A radar dot is not enough. The exception is the Targeting Facility: while you have one that is switched on, a unit that has no target in sight may also choose one among the radar dots. You can always order an attack on a radar dot yourself.

Worked Example

You play Core against Arm. An Arm Jammer parks beside a group of Bulldogs, inside the 1440 range of your Radar Tower. Within the Jammer's 400, the Bulldogs vanish from your radar, and so does the Jammer itself.

Send a Fink over the group. As soon as the Fink's sight of 350 reaches the Bulldogs, they appear, and your units can pick them as targets. Your own Core jammers, such as the Spectre, never hide anything from your own radar.