Finding and Exploring Eidolon Structures
Overview
This guide explains how to locate and explore the three main structures added by Eidolon:Repraised: the Stray Tower, the Catacomb, and the Lab. Each structure appears in different biomes and at different frequencies, so knowing what to look for will save you time.
Stray Tower
The Stray Tower is the most common structure. It generates in biomes tagged under `has_structure/stray_tower_biomes`. The game attempts to place one tower per 24x24 chunk region, with a minimum spacing of 18 chunks between towers. This means you will encounter them fairly often while exploring.
Inside a Stray Tower, monster spawning is overridden. This does not mean monsters are absent, but the normal spawning rules are replaced with the structure’s own spawn logic. Expect hostile encounters tailored to the tower’s interior.
To find a Stray Tower, travel in a straight line across the appropriate biomes. Since the placement is region-based, walking a few thousand blocks in one direction will usually reveal one. Towers are tall and visible from a distance, so keep your render distance high and scan the horizon.
Catacomb
The Catacomb is the rarest structure. It generates in any biome tagged under `minecraft:is_overworld`, meaning it can appear in most surface biomes. However, the placement is sparse: one attempt per 80x80 chunk region, with a minimum distance of 40 chunks between catacombs. This makes them roughly ten times rarer than Stray Towers.
Catacombs are underground. You will not see them from the surface. Instead, look for telltale signs: a small entrance structure, a depression in the ground, or a stone doorway partially buried. If you are not finding them by sight, use a methodical search pattern. Pick a direction and walk in a grid, checking every few hundred blocks for surface anomalies.
Monster spawning is also overridden in Catacombs. The halls are dark and cramped, so be prepared for close-quarters combat. Bring torches, food, and a good weapon before descending.
Lab
The Lab generates in biomes tagged under `has_structure/lab_biomes`. Placement is one attempt per 32x32 chunk region, with a minimum spacing of 8 chunks. This spacing is tight, so Labs can appear relatively close to each other. In practice, you may find several Labs within a few thousand blocks.
Labs are typically partially above ground or have a visible entrance. Look for unnatural blocks, metal plating, or a structure that does not match the surrounding terrain. The interior is dangerous, and monster spawning is overridden here as well. Expect a mix of hostile mobs and environmental hazards.
Because Labs are spaced only 8 chunks apart, once you find one, you can often find another by walking in any direction for about 500 blocks. This makes them the easiest structure to farm or revisit.
General Exploration Tips
- Bring supplies: All three structures override monster spawning, so you cannot rely on natural light to keep you safe. Carry torches, blocks to seal entrances, and healing items.
- Mark your path: Use torches or blocks to mark explored corridors, especially in Catacombs where getting lost is easy.
- Check ceilings and floors: Some structures have hidden rooms above or below the main path. Look for gaps in the ceiling or suspicious floor patterns.
- Return trips: If a structure is too dangerous, clear the entrance, block it off, and return later. The structure will not reset while you are away, but the mobs will remain where you left them.
- Use the biome tags: If you have access to commands or a map tool, check the biome tags listed above to narrow your search. Otherwise, learn which biomes feel “right” for each structure and focus your exploration there.
Summary
Stray Towers are common and visible. Catacombs are rare and underground. Labs are frequent and semi-exposed. Each has its own spawn rules and layout, so adapt your strategy accordingly. Start with Stray Towers to learn the mod’s structure design, then move to Labs for more frequent encounters, and tackle Catacombs only when you are well-equipped.
Covers the mod’s in-game guide topics: Stray Tower Catacomb Lab