Why is fit to world inactive ?

[MoonBeam]

[Peter]

Hi @MoonBeam, the Gaia Spawner can only display the visualization and perform a single spawn within a certain heightmap resolution limit. This is a hard technical limitation in the engine and the way the visualization works. If your world exceeds that size, that button will be locked.
You can still preview / visualize parts of the world by moving the spawner around to the position you want to visualize. If you want to apply the spawner to the entire world automatically this can still be done by using the "Spawn World" button (as opposed to using "Spawn Local" which will only spawn within the spawner range).
When using "Spawn World" on larger world the spawner will automatically be called multiple times on different positions until the entire world is covered.