lordpipe

In case it helps track down the true origin of this behavior, I reproduced it down to 14w29a, the update where block cracking animations first displayed on blocks like beds, chests, and signs.

Regardless of whether it was intentional I do think the behavior has a real-world realism and logic to it, as it lets you can stand under something and hack away at it with the very tip of your tool/hand from below, but at a reduced speed.

Huh? It’s pretty obvious this behavior is intentional.

It’s now fully fixed

This isn’t fixed. See my comment on MC-301333 (private issue since it is effectively a vulnerability)

If anyone needs to mitigate this in PaperMC 1.21.5, to restore full size hitbox before 1.21.6 officially comes out:

1. Download the PaperMC source code with git

2. Place this file at paper-server/patches/features/9999-Revert-broken-nether-portal-hitbox-MC-101556.patch:

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: lordofpipes <>
Date: Sun, 20 Apr 2025 21:47:16 -0600
Subject: [PATCH] Revert broken nether portal hitbox MC-101556
diff --git a/net/minecraft/world/level/block/NetherPortalBlock.java b/net/minecraft/world/level/block/NetherPortalBlock.java
index 2f08780430fc643991ffb4aeba1f1ae8e78944d2..6c5629a6f5f91496a55eb0bf281ceae1567915b1 100644
--- a/net/minecraft/world/level/block/NetherPortalBlock.java
+++ b/net/minecraft/world/level/block/NetherPortalBlock.java
@@ -63,11 +63,6 @@ public class NetherPortalBlock extends Block implements Portal {
         return SHAPES.get(state.getValue(AXIS));
     }
 
-    @Override
-    protected VoxelShape getEntityInsideCollisionShape(BlockState state, BlockGetter level, BlockPos pos, Entity entity) {
-        return state.getShape(level, pos);
-    }
-
     @Override
     protected void randomTick(BlockState state, ServerLevel level, BlockPos pos, RandomSource random) {
         if (level.spigotConfig.enableZombiePigmenPortalSpawns && level.dimensionType().natural() // Spigot

1. Generate the patched source code with ./gradlew applyPatches

2. Compile a paperclip jar with ./gradlew createMojmapPaperclipJar

3. The compiled jar will be at paper-server/build/libs/paper-paperclip-1.21.5-R0.1-SNAPSHOT-mojmap.jar