There are several launch arguments you can pass to the VU executable to enable different features and modify the client / server behavior. See below for a full listing of all available arguments.
These arguments can be used when running a VU server or client.
Used to explicitly specify the Battlefield 3 installation directory.
Writes a performance profile to
Specifies the Zeus environment to connect to. Defaults to
Specifies the update branch to fetch updates from. Defaults to whatever
-env is set to.
Traces DataContainer usage in VEXT and prints any dangling DCs during level destuction.
Sets a custom CA certificate bundle to use for SSL verification.
-activate -o_mail <email> -o_pass <pass>
Activates BF3 on the current machine using the specified Origin credentials.
Allocates an external console window for debug logging.
Saves logging output to a file in the logs folder. For servers, this folder will be in the server instance directory. For clients, it will be in the VU AppData installation folder.
Enables verbose logging.
Enables VEXT remote debugging, connecting to the debugger at the specified
host:port (this does not currently work). It also prevents the server / client connections from timing out and makes it so compiled VEXT modules sent to the client contain debug symbols.
Enables VEXT execution tracing. When tracing is enabled and VU crashes, the last executed line of each loaded VEXT mod will be available from the crash dialog and in the submitted crash details. Keep in mind that this could adversely affect performance.
These arguments only have an effect on the VU client.
Enables WebUI debugging at
Connect to a server with the given GUID (without dashes) and an optional password. This is the ID of a server key. You can also use this URL as a hyperlink on a website to join a server.
Example (with password):
Connect as a spectator to a server with the given GUID (without dashes) and an optional password. This is the ID of a server key. You can also use this URL as a hyperlink to join a server as a spectator.
Example (with password):
Enable verbose debugging logging for CEF. Useful for catching issues with WebUI mods. When running with this argument, a
debug.log file will be created in the directory of VU (usually
-username <username> -password <password>
Logs you in to your VU account using the specified VU credentials.
These arguments only have an effect on the VU server.
The two required arguments for running a VU server.
Sets the VU server frequency to 60Hz.
Sets the VU server frequency to 120Hz.
Runs the VU server in headless mode (without creating any windows).
Sets the server instance path (where the server configuration, logs, and mods are stored) for the VU server.
Enables high resolution terrain. Useful for extending maps beyond their original play area.
Disables interpolation between different terrain LODs.
Disables level checksum validation on client connection.
Sets the host and port the VU server should listen for connections on. Defaults to
Sets the port the VU server should listen for MonitoredHarmony connections. Defaults to
Sets the host and port the VU server should listen for RCON connections. Defaults to
Makes the server not show up in the server list. Unlisted servers can only be joined by the
connect console command or via the
vu://join/server-id url scheme, which can also be added as a launch argument to
vu.exe to auto-join as soon as the client loads.
Specifies the IP address clients should connect to in order to join this server. Only IPv4 addresses are supported. If you don't specify this, the backend will attempt to automatically detect the server's IP address.
Specifies a hostname clients should use when connecting to this server. When this is specified
-joinaddr has no effect and any clients attempting to connect will not attempt to perform any NAT detection.
Disables automatic updates.
Sets the maximum players that are allowed to set with
When using the default spectator size of
24, you won't be able to set
vars.maxPlayers higher then
40. Unless you reduce the spectator count before.