The Environment Query System (EQS) is a feature within the Artificial Intelligence system in Unreal Engine 5 (Unreal Engine) that is used to collect data from the environment. Within EQS, you can ask questions about the data collected through a variety of different Tests which produces an Item that best fits the type of question asked.

The conceptual idea and theory behind EQS come from Unreal Engine 3's Environment Tactical Query (ETQ) system which you can read more about in the following article, Asking the Environment Smart Questions. EQS Query assets can be created in the Content Drawer and can be edited inside a special Environmental Query Editor.

The Environmental Query Editor is a node-based editor where you can add a Generator node to produce Items, add your desired Tests to run on those Items and the Context in which to run them. Unreal Engine supplies many Generator types by default, however, you can create your custom Generators through Blueprint (or C++ for even faster execution).

The UEnvQuery class inherits from UDataAsset that, as the UE4 documentation states, is the “base class for a simple asset containing data”. The easiest way to setup this data is to keep a reference to an UEnvQuery in your Controller. UPROPERTY(EditAnywhere, Category = “AI”) UEnvQuery *FindHidingSpotEQS;