Timetabling double periods

[stfachtnasdls]

Hi, I am considering using FET to create the timetable for an Irish high school. One of the constraints I have is that I have to timetable double periods (two periods consecutively on the same day) for certain subjects such as Science, Woodwork, PE and Graphics. Is this possible using FET? Another constraint is that certain optional subjects are set to be timetabled against each other, e.g. Chemisty, Geography & Business must be on at the same time for fourth years as these students pick one of these three subjects.
Thanks for your time.

[Volker Dirr]

both is possible.
you can use normal constraints for the first point.
the second point should be solved by a correct students structure, because then you will get much better timetables instead of using "normal" constraints.
please read http://www.timetabling.de/manual/FET-manual.en.html#id_12

[Liviu Lalescu]

For the first request you can add activities with duration 2, or constraint two activities grouped.

For the second request, you have constraints activities same starting time.