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 event triggered by placing an Eternia Crystal Stand and an Eternia Crystal. The event spawns enemies that attack in waves, and the goal is to defend the crystal from being destroyed. The event can be challenging, especially in higher tiers, so building a base that avoids or mitigates the event is crucial for maintaining a safe and functional home.

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 surface. The event will only occur if the crystal is activated, and enemies will spawn from both sides of the stand. The event is designed to take place in a specific area, so if you build your base far enough away from the stand, you can avoid the event entirely. However, if you want to keep the stand nearby for convenience, you need to design your base in a way that prevents enemies from reaching it.

Step-by-step instructions for building a safe base start with location selection. Choose a spot far from your main base, preferably in a biome that is easy to access but not near your NPC housing or storage areas. This ensures that the event does not interfere with your daily activities. Once you have a location, place the Eternia Crystal Stand on a flat surface, ensuring it is at least 100 blocks away from your main base. This distance will prevent enemies from wandering into your base during the event.

Next, focus on building defenses around the stand. Create a barrier using blocks that enemies cannot pass through, such as solid blocks or walls. You can also use traps and lava to deter enemies, but be careful not to make the area too difficult for yourself to navigate. Place platforms or bridges to allow easy movement during the event, and consider adding teleporters for quick escapes if needed.

Important tips and considerations include ensuring your base has proper lighting, walls, and furniture to meet NPC housing requirements. NPCs can help defend your base during invasions, but they are not effective against the Old One's Army. Therefore, it is better to keep them safe in a separate area. Additionally, make sure your base has adequate storage for resources and crafting stations for convenience.

Common mistakes to avoid include placing the Eternia Crystal Stand too close to your base, which can lead to enemies overrunning your home. Another mistake is not having a clear escape route during the event, which can result in losing valuable items or being overwhelmed by enemies. Always plan your base layout with these factors in mind.

Advanced techniques and optimizations involve using wiring and traps to create automated defenses. For example, you can set up dart traps or flame traps to target enemies as they approach the crystal. You can also use actuators to create hidden passages or barriers that can be activated during the event. These techniques require advanced knowledge of wiring and mechanics but can significantly improve your base's safety.

Resource requirements and preparation include gathering materials for building, such as stone, wood, and metal bars. You will also need wiring components for traps and teleporters. Prepare by mining and crafting these materials in advance, and consider setting up a dedicated storage area for event-related items.

Class and equipment considerations are important if you plan to participate in the event. Melee classes can benefit from high-defense armor and weapons, while ranged and magic classes should focus on high-damage output. Summoners can use minions to help defend the crystal. Equip accessories that boost your combat abilities, such as the Warrior Emblem or Magic Cuffs.

Specific examples and scenarios include building a base in the sky or underground to avoid surface-level events. Sky bases can be accessed via ropes or wings, while underground bases can be fortified with traps and barriers. Another scenario is creating a themed base, such as a castle or fortress, that incorporates defensive elements like moats and towers.

In conclusion, building a base safe from the Old One's Army requires careful planning and execution. By understanding the event mechanics, selecting a suitable location, and implementing defensive strategies, you can create a base that remains secure and functional. Avoid common mistakes, utilize advanced techniques, and prepare adequately to ensure your base is ready for any challenge.