Copy That Building

Client-only Fabric utility by Mikasa for copying building regions from already loaded client chunks into export files.

Built for builders, server admins, and anyone who wants to save a build before it's gone. Copy fortresses, spawns, arenas, or your own creations from any world you have access to — then rebuild them later in your own world or server. This mod only reads and exports. Pasting back into a world is handled by a separate server mod (Place That Building).

Why use Copy That Building?

• Client-side only — no server install, no permissions needed to copy.
• Background scanning — the mod reads chunks on a worker thread, so movement and input stay smooth.
• Progress HUD — see chunks done, fill %, RAM usage, and estimated save size at a glance.
• Waypoint to missing chunks — a through-wall marker shows where you still need to walk so chunks load.
• Soft cancel — pause scanning and keep progress instead of losing everything.
• Four export formats — JSON, vanilla NBT, WorldEdit .schem, and Litematica .litematic.
• No keybinds — commands and menu only, so the mod leaves no trace in the keybind registry.
• No chunk forcing — the mod only reads what is already loaded, it never asks the server for more.

Features

• Copy any box defined by two corners (point A / point B) plus Y Min / Y Max
• Reads only fully loaded client chunks — no chunk forcing
• Background worker thread — scanning and saving should not freeze movement or input
• Progress HUD: chunks done, fill %, RAM / estimated save size
• Waypoint to the nearest still-needed unloaded chunk (through-wall marker while looking at it)
• Storage modes: RAM (default) or FILE (live JSON flush while scanning)
• Soft Cancel (keep progress) vs hard Stop (free RAM, delete temp file)
• Changing A/B rebuilds the zone: overlapping scanned chunks are kept, the rest is discarded, progress updates
• Export formats: JSON, vanilla NBT, WorldEdit .schem, .litematic
• Remappable commands via commands.json

- English UI labels (menu)

Requirements

• Minecraft 26.3
• Fabric Loader ≥ 0.19.3
• Fabric API
• Java 25+

- Client only — server install not required

Quick start

1. Look at a block → /copybuilding setpointA
2. Opposite corner → /copybuilding setpointB (reading starts when both are set)
3. Open menu → /copybuilding openmenu
4. Adjust Y / filters if needed → Update
5. Walk so needed chunks load (follow the waypoint if shown)
6. Choose format → Save
7. Chat shows: Saved: ctb-yyyyMMdd-HHmmss.<ext> (N%) Exports go to: .minecraft/config/Mikasa-copy-building/exports/

text

Example scenario

You are on a server and see a fortress you want to rebuild in your own world.

1. Stand at one corner and run /copybuilding setpointA.
2. Walk to the opposite corner and run /copybuilding setpointB.
3. Scanning starts automatically. Open the menu with /copybuilding openmenu to adjust Y range or filters.
4. If some chunks are still missing, follow the on-screen waypoint until they load.
5. When the progress bar reaches 100%, run /copybuilding save schem.
6. The file lands in .minecraft/config/Mikasa-copy-building/exports/.
7. Later, in your own world, paste it with WorldEdit or Place That Building.

Commands

Command names are remappable in: config/Mikasa-copy-building/commands.json

text

Restart the client after editing that file.

How scanning works

• The selection is a box from A/B on X/Z and Y Min…Y Max vertically
• Any remaining loaded chunk can be read (not stuck on queue order) — works with low view distance
• If no needed chunks are loaded, reading pauses; progress is kept
• When you enter a needed chunk, it is read and the bar moves
• Filename is automatic: ctb-yyyyMMdd-HHmmss (session start time)

Changing points A / B

• Builds a new zone
• Already scanned chunks that still fully cover what the new zone needs stay in memory
• Chunks outside the new box are cleared

- Progress becomes kept / newTotal

Storage

Stop clears RAM and deletes the live FILE json. Points A/B are kept.

Export formats

| LITEMATIC | .litematic | Litematica (single region) |

Filters (menu)

• Exclude air / grass / flowers / dirt / water
• Block id list with Exclude or Include mode

Example: minecraft:stone, minecraft:oak_log

Notes

• Does not place blocks
• Does not use keybinds (commands + menu only)
• Does not load unloaded chunks for you — walk (or raise view distance) so they load

- Use on worlds/servers you are allowed to copy from

License

MIT — Author: Mikasa