
forgematica Patch Mod
Forgematica Patch for NeoForge 21.1.235 Fixes IllegalAccessError caused by private access to BufferBuilder.building.
⬇ Download on ModrinthForgematica Patch
This mod restores compatibility between Forgematica 0.4.2 and NeoForge 21.1.235.
Without this patch, loading a schematic causes Forgematica to crash with an IllegalAccessError caused by access to the private BufferBuilder.building field.
The patch uses a small Mixin compatibility layer without modifying Forgematica itself.
Requirements
- Minecraft 1.21.1
- NeoForge 21.1.235
- Forgematica 0.4.2
- MaFgLib 0.4.3
Problem
Without this patch, loading a schematic causes Forgematica to crash with:
java.lang.IllegalAccessError:
class fi.dy.masa.litematica.render.schematic.BufferBuilderCache tried to access private field
com.mojang.blaze3d.vertex.BufferBuilder.building
This patch resolves the compatibility issue on NeoForge 21.1.235.
Solution
This patch restores compatibility between Forgematica 0.4.2 and NeoForge 21.1.235.
Notes
This is a compatibility patch only.
It does not add new features or change Forgematica's functionality.
It does not modify any Forgematica files.
It can be removed at any time without affecting your worlds or schematics.
- Edition: Minecraft Java
- File type: .jar
- Minecraft version listed: 1.21.1
- How to install: Install the matching mod loader (Forge, Fabric or NeoForge) for your Minecraft version. → Download the .jar. → Put it in the .minecraft/mods folder and launch that loader profile.
- Where to get it: Opens on Modrinth — not every file is mirrored on our own servers.
Install steps are the general flow for this file type — How to install Minecraft Java mods & modpacks walks through it step by step.
- Ships as forgematicapatch-1.0.0.jar — drop this file into the mods folder
- Download size: 6 KB
- Download link checked 27 Aug 2026 — working
These come from our own check of the pack file, not from the source page.