Collaborative writing and investing characters with a soul

The treatment I've been working on over the last couple of days - which I still can't put a name to - is the latest in a line of collaborative writing projects. Each collaboration has had its own distinct personality. Perhaps that's why I have enjoyed the process so much.

With the present - nameless - treatment, I am working with two other writers. The process has been as follows:

1) Meeting to agree on the objective. In this case, to write a screenplay that could be filmed on a tight budget.

2) Producing as many story ideas or partial ideas as possible. We didn't worry about practicality at this stage. Any idea, however crazy, was thrown into the collective pot. This stage lasted 2 weeks and was carried out with the aid of Google Groups but without physically meeting.

3) Meeting to plough through the 40 or 50 ideas, selecting the five most promising. And from that shortlist, choosing one to work on.

4) The chosen idea was given to one of us to work into a very brief story outline, in which the main plot points were identified and arranged in a three act structure. The outline was then circulated via Google Groups.

5) Meeting to discuss problems and missed opportunities in the outline.

6) The outline was then given to a different team member to take away and rework in the light of the last discussion.

Stages 5 and 6 were then repeated. At some stage the outline became a treatment. We have gone through three such repeats so far. Each time the number of problems reduced. But so far I've not noticed any reduction in the number of new ideas being introduced each time. Thus the quality of the product seems to me to be increasing steadily.

How long will we go on with this before deciding that it is time to start writing the screenplay itself? I guess that will come very soon. Whilst we could no doubt continue to refine the plot there is a limit to how far one can progress without putting words into the mouths of the characters.

In my experience giving characters voices deepens your understanding of their personalities. They had bodies before but dialogue gives them souls. And when they have souls you start to understand what the story is really about.

We meet again on Monday. I'll update you on progress after that.