Games of this style feature 3D polygonal graphics and real-time action. Real-time strategy games usually involve warfare between two or more forces. Opponents begin in different areas of the same map and develop their forces simultaneously. Typically, this involves establishing a base, harvesting resources, and deploying troops. Players strive to quickly develop superior forces, so strategy comes in deciding where and when to attack the enemy. The 3D polygonal graphics allow for realistically varied terrain, with elevation differences that may affect reconnaissance and combat tactics.