iafdragonfix
by yuuka0desu
IAF Dragon Den Fix is a Forge mixin mod that stops Ice Fire's dragon dens from placing roosts outside the chunks the game has loaded during world generation.
What it does
Ice Fire's dragon roosts can be placed across a radius of 30 chunks or more and carve into caves, sometimes 20 or more roosts in one world. When a structure lands near the world border or a chunk loading boundary, the generation code tries to reach chunks that are not in the WorldGenRegion cache, which throws a RuntimeException and can corrupt the save at that position. The mixin intercepts two methods inside WorldGenRegion so that roost placement stays within the chunk region that is available, which resolves the crash on both the server and the client.
The fix is lightweight and only touches the world generation path that causes the problem. Ice Fire is described by its author as compatible with other IAF addons, and the mod can be added or removed at any time. The mod is released under the MIT License and is not open source.
Key features
Roost placement limited to loaded chunks
Dragon roosts are kept inside the region of chunks that are available during generation, so they stop reaching past it.
Crash prevention near world borders
Structures near the world border or a chunk loading boundary no longer trigger the out-of-bounds chunk access.
Two WorldGenRegion methods intercepted
A Mixin hook on two WorldGenRegion methods makes the change without replacing the generation code wholesale.
Safe to add or remove
The mod can be installed or removed on an existing world without a reset, and the author states it works alongside Ice Fire.
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Use cases
Servers running Ice Fire
Server owners who run Ice Fire on a world with a border or large generated area can install the fix on the server to avoid the crash and save corruption.
Who it’s for: Server owners and players who use Ice Fire on Forge 1.20.1 and see dragon roosts placed in unexpected places or crashes during generation near the world border.
Questions
Does IAF Dragon Den Fix need to be installed on the client?
Does Ice Fire need to be installed for this mod to work?
More from yuuka0desu
What the author says
IAF Dragon Den Fix A lightweight Forge mixin mod that fixes a server/client crash caused by Ice and Fire's Dragon Dens and Dragon Roosts generating outside the available chunk region. The Problem Ice and Fire's dragon dens and roosts place blocks across a large radius (30+ blocks for caves, 20+ for roosts) during…
Official listing
- Modrinth page
- modrinth.com/mod/iafdragonfix
- Owner
- yuuka0desu
- Published
- 2026-05-28
- Updated on Modrinth
- 2026-09-23
- Facts verified
- 2026-10-15