How can I build a base in Terraria that is safe from Old One's Army events?

To build a base in Terraria that is safe from the Old One's Army events, you need to understand the mechanics of the event and how it interacts with your world. The Old One's Army is a wave-based defense event triggered by placing an Eternia Crystal Stand and an Eternia Crystal. The event spawns enemies that attack in waves, and your goal is to protect the crystal from being destroyed. However, if you want to avoid the event entirely, you need to ensure your base is not near the event's activation zone.

First, let's discuss the mechanics. The Old One's Army event is tied to the Eternia Crystal Stand, which must be placed on a flat, open area. The event spawns enemies from both sides of the stand, and they will target the crystal. If you place the stand too close to your base, enemies may wander into your base area, causing chaos. To avoid this, you need to build your base far enough away from the stand so that the event does not interfere with your structures or NPCs.

Step-by-step, here's how to build a safe base. Start by choosing a location for your base that is at least 100 blocks away from where you plan to place the Eternia Crystal Stand. This distance ensures that the event's enemies will not pathfind into your base. Next, construct your base with sturdy materials like stone or wood, and ensure it has proper lighting, walls, and furniture to meet NPC housing requirements. Make sure your base has multiple layers or floors to accommodate all your NPCs and storage needs.

When building, consider adding defensive measures like traps, lava moats, or walls to keep regular enemies out. While these won't stop Old One's Army enemies, they will help protect your base from other threats. Additionally, place your NPCs in secure rooms with doors that can be closed to prevent them from wandering into danger.

Important tips include avoiding building near the Dungeon, Jungle, or Corruption/Crimson biomes, as these areas can complicate your base's safety. Also, ensure your base has easy access to crafting stations, chests, and other essential utilities. If you plan to fight the Old One's Army later, consider building a separate arena near the Eternia Crystal Stand, far from your main base.

Common mistakes to avoid include placing the Eternia Crystal Stand too close to your base, which can lead to enemies invading your structures. Another mistake is not securing your NPCs properly, leaving them vulnerable to attacks. Additionally, avoid using flammable materials like wood in areas where enemies might spawn, as fire-based enemies can destroy your base.

Advanced techniques include creating a teleporter network to quickly move between your base and the Old One's Army arena. This allows you to participate in the event without risking your base's safety. You can also use actuators to create hidden doors or traps that can be activated during emergencies.

Resource requirements for building a safe base include plenty of wood, stone, and other building materials. You may also need wires, actuators, and traps if you plan to add advanced defenses. Preparation involves gathering these materials early in the game and planning your base layout carefully.

Class and equipment considerations are less critical for base safety but still important. If you plan to fight the Old One's Army, ensure you have strong weapons, armor, and accessories suited to your class. For base building, tools like the Architect Gizmo Pack can help with precise placement of blocks and furniture.

In specific scenarios, such as multiplayer, coordinate with your team to designate areas for the base and the Old One's Army arena. This prevents confusion and ensures everyone knows where to go during the event. In single-player, focus on creating a compact, efficient base that meets all your needs while staying safe from the event.

By following these steps and tips, you can build a base in Terraria that is safe from the Old One's Army events, allowing you to focus on other aspects of the game without worrying about invasions.