The surface mark of an established plume is a hot spot—an isolated region of volcanoes and uplifted terrain located far from the edge of a surface plate.

The standard Create unit has special sensors for other events, such as when the unit bumps into a wall or object and when the unit is at the edge of a surface like a table.

This produces the effect of a bright highlight on the edge of a surface that faces away from lights in the scene, while edges that face lights directly have their highlights obfuscated.