When all the people are defined and the project file is saved the simulation can begin. Select the Menu Item: Simulate > Begin. A dialogue box will appear and ask whether the simulation shall be recorded for later play-back. This feature works like a tape-recorder. Choose Yes and define the filename of the play-back file, which shall have the extension .SLX. Be aware that the .SLX files can reach significant sizes, depending on the size of the population and the evacuation time.
The simulation of large numbers of people can take a long time (sometimes many hours), depending on the speed of your PC. If you are simulating the evacuation of a large, crowded population you may need to let the calculation run overnight or at a weekend, and then play back the recorded evacuation at a later time. Note that the playback files can become very sizeable for large populations. For example if 200 people leave within 2 minutes, then the playback file may only be 3 - 5 Mb, but if you are modelling the movement of thousands of people the playback may be greater than 50Mb.
As the evacuation progresses, you will see people progressing towards exits, in simulated movement steps of 0.1 seconds. The number of people and simulation time are updated every 0.1 seconds in the Information Window.
Figure 9: Sample screen display of a crowded area
The response of the program may slow down if many people are being modelled. This is because Simulex only process Windows messages (commands) after each single time-step calculation is completed for the whole population. You will notice this effect especially when you have large, crowded populations. To pause a simulation, just click once onto the Simulation menu, and wait for it to respond - it will usually respond when it has finished one calculation step for the whole population. The best way to interrupt a simulation is to make sure that a floor plan or staircase window is the currently focused window, and press F8. The evacuation will pause when the next time-step calculation is finished. The processing of Windows commands is slowed down to try to make Simulex calculations as fast and uninterrupted as possible.
When the simulation is finished the total evacuation time is displayed together with a question asking if an output file shall be created. This file, a normal text-file, contains basic data about the simulation such as the total evacuation tile, number of persons on each floor, number of exits, etc. The output file has the extension *.txt and can be read by all word processors.
The play-back of a simulation can be performed by choosing the Menu Item: Simulate > Playback. The play-back will be performed in almost real time depending on the performance of your PC. It is also possible to play the file step by step forward or backward. Choose Pause and the sequence stops. By using the function keys F2 and F3 the recording can take one step back or forward at the time. Each step is 0.1 second.
