In Tiberian Sun, the engineer became the linchpin of the cheapest tactic in the game.The Engineer: Engineers can repair bridges and your buildings, capture enemy buildings.Enemy Exchange Program: Standard for Command & Conquer games, Engineers can capture enemy buildings and partially or fully make use of the enemy arsenal.Demolitions Expert: The official strategy guide for Tiberian Dawn explains how Engineers can capture enemy buildings so fast � they're trained so well in the use of shaped charges that they could walk straight through a bank vault without changing pace.Combat Medic: In Renegade, they can heal troop as well as repair vehicles and are often brought along for the steady HP restoration in-combat.Bomb Disposal: In Renegade, Engineers's Repair Guns can also disarm enemy C4 and beacons by draining their health bar (nothing else can damage these things).All Your Base Are Belong to Us: An engineer raid in any of the games can easily see half your enemy's base fall to you in one fell swoop.
Although (usually) unarmed, Engineers are important assets on the battlefield since they can capture enemy and tech structures and instantly repair one's own.