Processes have steps with different calculation modes. Calculation mode is the way steps handle changes in their dates and durations. Calculation mode can be:

Duration driven:

• Step depends only on it's duration.
• Step start date is automatically calculated by system based on date when previous step has been ended (or when process has been started - for first steps).
• Step end date is simply calculated by adding step duration interval to start date.
• When previous step end date is changed, this step dates are shifted too to make step start immediately after previous one.

Date driven (soft):

• Step dates are set by user or by system at planning stage.
• Step dates are recalculated by system based on date when previous step has been ended.
• Step end date is simply calculated by adding step duration interval to start date.
• When previous step end date is changed, this step dates are shifted too keeping step relative date/time position. This means if there is a gap (positive or negative) between previous and current step, it will not be changed.

Date driven (hard):

• Step dates are set by user or by system at planning stage.
• Step end date is simply calculated by adding step duration interval to start date.
• Step dates are not affected by previous step dates changes.