Adaptive Starting Structure

Adaptive Starting Structure lets modpack creators decide where a new world should truly begin.

When a world is created, the mod chooses one of your custom structures, looks for a suitable location near the original spawn, prepares the surrounding terrain, and places the structure before the player enters the world. The selected spawn point then becomes the world spawn.

What the mod does

The mod is designed for starting bases, ruins, crashed vehicles, underground shelters, quest hubs, or any other build that should define the opening of a modpack.

Instead of placing the structure on the first available patch of ground, it searches for a location that fits it. It considers the terrain, biome, water, available space, spawn safety, and the horizontal rotations allowed in the config. If more than one structure is available, the world seed determines which one is selected.

Before placement, the chosen site is checked again against the terrain that was actually generated. If it is not suitable, the mod can try another planned location. It also avoids intersecting generated Minecraft, datapack, or modded structures.

Once a safe site is found, the mod:

levels the ground beneath the structure without exceeding the configured limits;
blends the surrounding terrain into the structure instead of leaving abrupt walls or floating edges;
removes complete trees that would intersect the build or the terrain being changed;
places the structure in one of its allowed rotations;
checks that the marked spawn position is safe;
sets that position as the new world spawn.

All of this happens during the creation of a new world. Existing worlds are not given a starting structure retroactively.

How to use it

Adaptive Starting Structure requires Minecraft 1.21.1 with NeoForge. Add the mod to the client and server, then place at least one Minecraft structure template in:

config/adaptive_starting_structure/structures/

Templates must be direct .nbt files; subfolders are not scanned. File names must use lowercase letters, numbers, underscores, dots, or hyphens.

⚠️❗❗❗ Each template needs exactly two Structure Blocks in DATA mode:❗❗❗⚠️

adaptive_starting_structure:spawn marks the intended world-spawn position at the player's feet.
adaptive_starting_structure:ground_level marks one block above the terrain level that should meet the structure.

These marker blocks are only used to position the structure and are removed when it is placed.

In Minecraft 1.21.1, DATA mode is hidden. Place a Structure Block, set it to CORNER, then hold Alt while clicking the mode button once. Enter one of the values above in the Custom Data field, select Done, and repeat for the second marker. Both markers must be included inside the exported structure.

After adding the templates, create a new world normally. No command is required. The mod will select a structure, find a location, place it, and move the world spawn automatically.

Configuration

The common config lets pack creators adjust the search distance, preferred and excluded biomes, accepted amount of water and uneven terrain, terrain blending, cut and fill limits, allowed rotations, and spawn-area safety.

Entities saved inside a template are disabled by default. Set placeTemplateEntities = true if supported template entities should also be placed.

If a template contains blocks from a mod that is not installed, those positions become air. For the intended result, make sure every content mod used by the structure is present.

If placement is not possible

The mod is deliberately cautious about world creation. Invalid templates, invalid configuration, or planning problems found before anything is changed fall back to Minecraft's normal spawn and report the reason.

If every prepared location fails the final safety checks, singleplayer presents a choice: return to the world list and try another seed, or continue permanently with a normal Minecraft spawn and no starting structure.