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In the toolset find an encounter, draw a polygon on the ground. Simple as that - the area when entered will trigger the encounter (if the encounter is active).
The first point in the generated polygon is the location returned by GetLocation when used on the object.
The spawn point is optional (but highly recommended) since it should "spawn them outside of LOS" if not placed, but to place a related spawn point right click an encounter and select Add Spawn Point. Then place it down. This acts as an "anchor" for the spawn, although obviously one solo monster will spawn right on top of it. Note: There is no way to find these spawn points (or relate them to the parent encounter) since they are essentially just a "location" (they have no independent tag or anything).
These spawn points are invisible in the toolset unless an encounter is selected (presumably to not have the area lists massively over populated by them in larger areassince they're not true objects, only existing as part of the parent encounter info). The spawn points can be rotated only using the buttons on the bottom of the toolset (for some reason the only right click option is Delete). The rotation determines the rotation of the creatures that are spawned at that location.
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