Grid Placement 6.3 Guides

Development docs. These pages describe the unreleased 6.3 build. They become the live 6.3 guide set when that version ships; the 6.2 guides stay the published instructions until then.

The 6.2 guide set stays published as it is. These pages document the 6.3 change to who is placing: the session owns the placer, the positioner is a convenient Inspector adapter for it, and the PlacementOwner node is no longer part of a new setup.

Read them in this order:

• Getting Started (6.3) — download to first 2D placement through Setup Scene → Setup UI, one entry, one real click, and an actionable refusal. Start here.
• 3D Room Placement & Stacking — place a whole room as one entry and stand the same rooms on the storeys above, with the per-storey support rule and the refusals it produces.
• Placer Ownership — where the acting placer lives, how to bind it from the Inspector or from code, and the one precedence table that decides the effective value.
• Actor-Free Placement — when placement needs no actor at all, and how a rule that does need one refuses instead of silently placing.
• Migration from PlacementOwner — the three edits that remove the 6.2 node from an existing scene, and what still works if you keep it.
• The 6.3.0 rename — the retired noun, the one-to-one API mapping, and the gate that keeps it retired.

Everything in the 6.2 guides still applies to targeting, validation, catalog and persistence. Only the placer wiring changed.

Everything else is the 6.2 guide set

These stay at their published URLs; a 6.3 copy would only go stale.

Task	Guide
Placement rules and validation	Custom placement rules, Validation
The hover/targeting path	Targeting flow
Save, load, persistence	Save and load
3D GridMap work	3D object placement, 3D terrain painting, Nature and floors
Split-screen / multiplayer	Multiplayer and split-screen
Something is wrong	Troubleshooting

The full list lives at Grid Placement 6.2 guides.