Design Document or Prototype?

I’ve read a number of discussions that seemed to conclude that design documents are not as good as prototyping an  idea.  I thought I’d chime in because it seems to me that prototyping an idea assumes what amounts to a design document.

I think the issue may boil down to a difference in definition of a “design document”.  To me a “design document” is the written form of the conceptualization of the systems in the game.  The important part is not the document itself but rather the understanding of how the game works.  It seems one must have a clear understanding of how the various game systems interact with each other before you can create a prototype, and a design document is a hard copy of that understanding.  To me, the “design document” goes as far as high-level pseudocode and high-level system interface logic.  In many ways it’s tied up with the process of wrapping one’s mind around the game systems.

I can see how a small-ish team would not necessarily need a design document.  If they are working on a subsystem and the designer of that subsystem is part of the team, then assuming the designer truly has a complete understanding of how the subsystem works there does not need to be an official “design document”.  Instead, the team goes right on to making a prototype of the subsystem.

So, I think the elimination of a design document in favor of prototyping is not a universal debate that has a universal answer.  It’s a case-by-case basis.  From my experience though, writing out a thought typically results in improvements to that thought, and every single commentary on project management will support the notion that more planning at the beginning results in less heartache costs later on.

All that being said, I guess I consider prototyping as more of a proof-of-concept task than something that can replace a design document (as I think of them).  Once you have the system design figured out, using the creation of a design document as an aid, then you pick out those aspects of the system that need some confirmation, and you build a prototype to help determine the feasibility of the design.  I will most certainly agree that a design document is all pie-in-the-sky conjecture, not meaning a thing if it can’t be done.  However, the complexity of especially MMO virtual worlds seems to me to absolutely require extensive design conceptualization.

And maybe that’s the real issue here: virtual worlds are in many ways fundamentally different than “games”, and as such, “design document” means something different in that context than if it were being used in the context of making a first person shooter.