- Basic Concepts
- Logging records runtime events and function calls in text files
- UE_LOG macro outputs logs to files with customizable verbosity levels
- UE_LOGFMT introduced in UE5.2 provides cleaner syntax for basic types
- Log Access Methods
- Logs stored in ProjectName\Saved\Logs folder after Play-In-Editor sessions
- Real-time logging available in Output Log tab during Editor sessions
- Logs accessible via console command or executable shortcuts
- Verbosity Control
- Log verbosity levels range from VeryVerbose to VeryLow
- Default verbosity set in Engine.ini or DefaultEngine.ini
- Runtime verbosity can be changed via command line or console
- Custom Logging
- Custom categories can be created using DECLARE_LOG_CATEGORY_EXTERN
- Categories can be prefixed with "Log" for alphabetical sorting
- CompileTimeVerbosity must be set to "All" for proper logging
- Screen Messages
- Screen messages can be added using AddOnScreenDebugMessage()
- Messages can be displayed for specific time periods
- Viewport Stats Subsystem added in UE4.26 for viewport messages