The editor's Grid Placement → Setup commands build the plugin's side of a level for you: the host, the cursor, the level context, the objects parent, the session, and the selection panel. They do not build your game.
The two actions
Setup is two presses, in this order:
- Setup Scene — picks a level type (platformer, top-down, isometric, hex, 3D) and builds the rig: the host, the cursor, the level context, the objects parent, the session and the catalog.
- Setup UI — adds the selection panel and points it at the session the rig already uses.
The intermediate state is deliberately visible: after Setup Scene the rig exists and the host is ready, but there is no panel yet. A rig without the panel is not a finished setup.
What you bring
The setup gives you the plugin's nodes and editable resources. Your content is yours to author — the setup never invents it:
| You bring | Where it goes |
|---|---|
| Your scene objects (the props, the structures, the characters) | Your own scenes, instanced in your level |
| Your terrain definitions — the tileset and its terrains (2D) | The TileMapLayer's TileSet |
| Your terrain definitions — the mesh library and its items (3D) | The GridMap's MeshLibrary |
| The ground your objects stand on | Painted cells in your TileMapLayer / GridMap |
Nothing is painted for you and no placeholder mesh is created: an empty surface with no tileset or mesh library is the honest starting point, and placement on it is refused until your own ground is there. That refusal is the point — it tells you the level is not finished, rather than hiding it behind a box the setup invented.
Your catalog starts empty too. Entries are your definitions: a
ScenePlacementEntry per object, with the scene it places, its footprint,
its family, and its placement rules. The setup gives you the catalog; the
entries in it are yours.
What "ready" means
The host reports itself ready when the rig is composed: the services exist, the session is bound, and the consumers are wired. That says the plugin's side is sound. It does not say the level is playable — a rig with no entries, no ground and no panel can be ready and still do nothing.
A setup is finished when all of the following are true:
- your entries are in the catalog, and selecting one previews correctly;
- your ground is painted, and a placement commits and shows up in the world record;
- the panel is present and selects from the same session the rig uses.
Doing it by hand instead
Every node the setup creates is an ordinary scene node with ordinary
Inspector properties. You can wire it yourself, and a hand-wired level is
just as valid: give the host its PlacementSession and turn on
auto_configure, give the cursor its grid and camera, and add a
PlacementLevelContext with your map and your objects parent. The plugin's
own demos are wired exactly that way — see
3D Object Placement for the 3D case and
2D Object Scene Setup for the 2D case.