The function controlled overlap supports different kinds of overlap (send-ahead) between two operations. The function is available when double-clicking on an operation in the Gantt chart and the window Edit operation will show up, on the Times tab the settings for overlap is.

When using the scheduling strategies, the controlled overlap is taken into consideration.

Classic overlap

Classic overlap is when the following operation of the route, can start x percent, x elements, or x hours after the current operation is started. You achieve this by enabling the Apply overlap flag and entering the desired overlap offset.

The overlap is always calculated after Setup time end.

Note that to create two operations completely parallel, set the offset to 0. However in that case it may be better to use Anchor defined overlap explained below.

Allow end before this

By default, the scheduling rules will not allow, that the following operation ends before the actual operation. I.e. this to ensure that the following operations in all cases, wait for the complete amount from the previous operation.
In special situations, this can be overruled by enabling the flag Allow end before this

Fixed option

With the “Fixed” option it is possible to specify if the overlap should take shift calendar working hours into consideration or not

  • If “Fixed” mode is off (the default) the overlap hours are calculated only in open shift calendar periods.
  • If “Fixed” mode is on then shift calendar is not considered. For example, if the overlap is entered as 5 hours, the next operation can start 5 hours later even if the overlap period crosses a Sunday without any open working hours.

Anchor defined overlap

Another way to define overlap is to model the operation In and Out anchor. I.e. on the current operation set the Out anchor to e.g. Setup end. This will have the effect, that the following operation can start in parallel with the current operation. The pros and cons of this approach are


  • In and out anchors can be overwritten on the constraint itself. I.e. if you have a one-to-many relationship, then each of the many operations can have different overlaps (which is not possible with controlled overlap).
  • Constraint lines have many options which can be overwritten on the constraint line. Like hard-link next and more.
  • Classic overlap is always from after the Setup end. Out-going anchors can be set to other options also, like Switchover start, etc.


  • The Allow end before this option cannot be supported with anchor-defined overlap.


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