How to Fix Items Not Stacking or Floating After Installing ItemPhysic

Diagnosing the Problem

If dropped items hover in mid-air, refuse to merge, or jitter in place, the mod is either conflicting with another mod or its physics tick is being interrupted. This is almost always a mod-conflict issue, not a bug in ItemPhysic itself.

Step-by-Step Fix

1. Note exactly what is wrong: floating items, items that never merge, or items that fall through the ground. Each points to a different conflict.

2. Disable any other mod that touches item entities — drop-animation mods, item-physics mods, and some performance mods that optimize entity ticking are the usual suspects.

3. If you run a performance mod that culls entity ticks, add dropped items to its whitelist or disable entity culling for items. Culled items stop receiving physics updates and freeze in place.

4. Check that you are not running both the Full and Lite versions of ItemPhysic at once. Only one should be present.

5. Reload the world. If the problem persists, start a test world with only ItemPhysic and reproduce the drop. If it works there, the conflict is confirmed and you can bisect your mod list.

When It Is Not a Conflict

Very rarely, a chunk that fails to load will leave items suspended. Walking away and returning, or relogging, resolves it.