Constructing field works became increasingly popular during the Civil War, not the least because of the improved firepower of the weapons used. While during the early war entrenchments were simple, hastily constructed breastworks, by the end of the war, especially during the siege of Petersburg, the battlefield was covered with reinforced trenches and obstacles, making a head-on attack a very dangerous affair for the attackers, if the field works were fully manned.
You can build entrenchments for your troops during a battle. During the pre-battle deployment (which is the time they have at hand before the battle is joined), depending upon the readiness of your men, you can build breastworks (barricades) and trenches and upgrade existing trenches. Pontoons can also be laid in suitable locations if within the deployment zone.
To build an entrenchment, click on the appropriate button. With RMB, you can place the left edge of the entrenchment and then move the mouse; you will see a faint line indicating where the entrenchment would be placed. If the segments are shown as red, the terrain is not suitable; the area is out of reach, or you have no more engineering points available. Each click of the RMB creates a new point in the line and clicking on the LMB finishes the placement of the trenches. Moving the mouse over the faint entrenchment line shows a “cancel” cursor, and clicking on the RMB will remove the planned fortification.
During the pre-battle deployment phase, entrenchments are built up instantly. You can also spend engineering points to upgrade trenches that have already been built. There are four levels of entrenchment, each of which will improve the defensive value of the trenches. Move the cursor over the finished trench, and the cursor will change into “upgrade trench”: click on the RMB to make the upgrade: During combat, you can only erect barricades. These are planned according to the above description but need to be built by your infantry. Select the infantry unit, and move the mouse over the planned entrenchment. The cursor turns into “build,” and clicking on the RMB will order the men to build the barricade and then take position behind it.
Suitable pontoon locations are shown in the terrain as transparent pontoons. You need an engineering-capable unit to build pontoons. Select the engineers, move the cursor over the pontoon and click on the RMB to build; when you see the “pontoon” cursor.
Mouse over the cursors for construction: build (left), cancel (middle), upgrade (right).