Optimising of timetables automatically makes them more compact by eliminating their caps with a set of different kind of change, replace and move algorithms, which constitute a very complicated sequence of operations. The computer can search for those change options much faster than humans, since the number of possible combinations often grows exponentially comparing to the data file size. In selection Tools|Optimise|Optimise timetables you can control the optimisation process with several parameters.
Before timetables can be optimised, you should assign at least some oft the lectures into timetables, either manually in Timetables view or automatically in Tools|Optimise|Initial solution. Note that optimisation does not assign new lectures into timetables, does not remove them, but changes their positions according to specific rules.
You can also lock selected courses to exclude them from optimisation or set bookings to timetable slots to prevent undesired results. Creating of timetables is often a combination of interactive solution and optimisation. It is a good practice to assign first critical lectures manually in Timetables view, then lock those courses and possible save this solution on disk to ease experimenting with different automatic solutions.
Optimise enables to apply also certain rules for the patterns in timetables in order to prevent undesired results.
