What is the better way to splitt an activity?

[Chafik Graiguer]

I have an activity , total duration 4
I can enter it as one large activity splitted like this: 1+1+2 because this form is more preferable
However, how to give FET more freedom
so FET could split it 1+1+2 in most cases, and only 1+1+1+1 if there is no other choices (for example to unlock an impossible timetable)

[Liviu Lalescu]

This is probably not possible directly, because for FET 1+1+1+1 is better than 1+1+2. But maybe you can try this: add 1+1+1+1 (A1, A2, A3, A4) and constraint 2 activities grouped for A3 and A4 with 99%. It might work. In principle, the weight of grouped constraint should (99%) should be much greater than min n days between activities (default 95%).

As I think, you may use better this: add min 1 days for only A1, A2 and A3, 100%. Add min 1 day A1, A4, another min 1 day A2, A4, another min 1 day A3, A4, all with consecutive if same day=true and weight 0%.

[Volker Dirr]

I highly recomment/prefer Livius second variant.
But you can do it (very) similar with this shortcut:
Add activity 1+1+1+1 with min n day 1, weight 0% and check force conscutive if same day.
Then also add constraint A1+A2+A3 with min n day 1 and weight 100%.
That is (very) similar to Livius solution, but faster/easier to add.

Of course it is only 100% similar if A1, A2, A3 and A4 doesn't have any differences. So for example if you modify one (or more) subactivities manualy, then you should use Livius variant. Or if the constraint to the subactivities are not the same then you should also use Livius variant. (for example if you use subactivities preferd times constraint).
But in most cases you can use my shortcut.

[Chafik Graiguer]

Tanks a lot for hints
I will try this:

Add activity 1+1+1+1 with min n day 1, weight 0% and check force conscutive if same day.
Then also add constraint A1+A2+A3 with min n day 1 and weight 100%