Formula For Duration Between Tasks Based On Code Library Allocation

Hi All,

Following my last post (http://www.planningplanet.com/forums/asta-powerproject/537680/using-formula-answer-another-formula [1]). I’ve realised I need help with the actual formula;

I have a programme with multiple tasks per line / bar, with each task on a line having a different code library allocation. The bars are set so that tasks may overlap.

I’m trying to get the duration (start to finish – not cumulative) between the start of a task with Code Library Allocation “A”, and the finish of a task with Code Library Allocation “D”. The tasks don’t appear at the same task number (in the line), so I don’t think I can use the task number object selection.

Code Library has object id 35

Code Library Allocation A has object id 167652

Code Library Allocation D has object id 167654

The formula that I’d got to is below, but although the status is OK, it doesn’t give the answer is was after;

DateDiff(Task.CodeLibrary(35, 0, 167652).Start, Task.CodeLibrary(35, 0, 167654).Finish)

I’ve tried since tried simplifying it in stages but they don’t seem to work either;

Should give the start of task code library allocation A (object id 167652).

Task.CodeLibrary(35, 0, 167652).Start

Should give the finish of task with code library allocation D (object id 167654);

Task.CodeLibrary(35, 0, 167654).Finish

Any help would be appreciated

Kind regards,

Chris