Input form for Project planning

You would need to define a member in each dimension for any cell in the cube. So If you have project in UD1, you may have a small sub hierarchy in Accounts which includes a member for Start Date, End Date and Contract type. If you followed this approach you may have to use one of the annotation members in the view dimension to enter text in the cube. 

HOWEVER, you should consider a table based approach, e.g thing planning or a custom table as these may be better options for storing project information. We don't know your requirements but I would strongly suggest researching a table based solution.