During a building disaster, building occupants typically engage in herd behavior, which results in friction, pushing, and even injury and death. Building occupants crowding at exits increases the difficulty of an evacuation. By properly dividing building occupants, the problem of pushing can be diminished. In this study, various software packages were used to construct building models, and evacuation times were simulated under various evacuation conditions. In addition, obstacles were placed in front of exits to explore their effects on building occupant evacuation behavior. Unity and C# were utilized to develop software that could simulate building evacuations, and the simulation results were compared with those generated using EXODUS and Pathfinder. Moreover, the effects of installing obstacles at exits and changing exit widths, obstacle widths, and the number of occupants evacuated from the buildings on evacuation times were explored. The results indicated that by placing an obstacle in front of an exit, the evacuation time was reduced, especially when the width of the obstacle was close to that of the exit. However, when the number of building occupants reached 60 and the exits measured 120 cm wide or less, placing obstacles did not improve congestion much. The study results can be used as a reference by related departments to reduce the number of casualties as a result of crowding at exits as well as well as building occupants panicking and rushing for exits.