Create Collision Crashfix

The crash appears when a moving contraption's collision check reaches a degenerate case: the entity's bounding-box center lands exactly on the contraption block's center axis. Inside Create's ContinuousSeparationManifold, the separation axis is then recorded as Vec3.ZERO, the value is not stored, and collideMany dereferences it, which takes the server down. The most common trigger is a rope pulley driving a drill quarry, though drill arrays with a pulley center column, rotating bearings and tree farms with saws can hit it too.

The fix replaces the missing axis with Vec3.ZERO and pairs it with a separation scalar of Double.MAX_VALUE, so the degenerate path settles cleanly instead of crashing. The guard activates only on that path, and normal collision behaves byte-for-byte as before. The mod runs on client and server and is published for NeoForge 1.21.1 only, released under the MIT License as open source. The source code is public.

Only Create 6.0.10 has the upstream bug; Create 6.0.9 is unaffected, and the official fix (Create PR 10301) had not shipped in a 6.0.11 release at the time of writing. Packs often downgrade to 6.0.9 instead, but addons that depend on the newer release keep them on 6.0.10, so this patch serves packs that must stay there. The mod mirrors the intent of upstream PR 10301 with a deliberately surgical change.