## SIMULATION VARIABLES

SimVars are "simulation variables" and they are the way that third party APIs and add-ons can get information about the current state of the simulation. In general these variables are used to control aircraft behaviors by permitting you to retrieve data about things like weather conditions, position, or aircraft status, and in many cases they can also be used to modify something within the simulation, in particular aircraft instruments and controls - although they can also have many other purposes within any add-on package.

You can find detailed information about each particular SimVar on the following pages:

There is also a further section dedicated to Event IDs. These are used as a way to interface between different simulation systems, with the user at the top level the various sub-systems within the simulation at the bottom. You can find all these event IDs in the following section:

Finally, there is an additional document for Audio Design that lists the RTPC events and the SimVars they are associated with:

#### Note on SimVar Data Types

When accessing SimVars using the SimConnect API, you would first create a data definition using the function SimConnect_AddToDataDefinition and in that you would tell the simulation the data type for the variable. By default this is a 64 bit float, but for most simulation variables this can be almost any appropriate data type (that fits the unit of the SimVar) and the same data type should be used when getting or setting the value later. When a specific data type is required - for example SIMCONNECT_DATA_LATLONALT - this will be mentioned in the description for the variable.

NOTE: SimConnect has no BOOL data type. For this kind of value, you can use an int or a float, and the simulation will interpret 0 as false, and anything over 0 will be interpreted as true.

### Simvar Watcher

An essential tool when working with the various simulation variables and setting up an aircraft is the Simvar Watcher tool:

This tool permits you to connect to the simulation in real-time and view the values of almost any Simvar available, as well as set the Simvar to a different value (if the Simvar is settable). Find out more information on this useful tool here:

### SimVar Index

Below you can find indexed all the SimVars available, presented this way to facilitate finding the required variable at a glance or through the search system:

ZERO_LIFT_ALPHA