How much spit and polish should be on a game design doc from the get go? Should I do a preliminary design doc and add to it as I go along or buff and polish the doc before going into the art work/programming step? I do know a good design doc can make or break a project, with a few notable exceptions (UT), and I want to do one. Also, should I put my current hobby project on hold and do some practice projects (as suggested by a gamedev.net article) suggests or dive into my current hobby project? I have some game development experience (no completed projects, though) and am looking to license and engine since that would save time.

Design docs really depend on the project. Are you the only one working on it? Usually a good design doc has two levels. One is a high level of what everything should look like when complete, the other is technical. The technical design would definitely need lots of detail if there are many programmers working on this. You need to know who is interfacing with who and where.
Licensing an engine can be expensive so it may be a good idea to get your feet wet first. Maybe start with a mod or play with some freebie engines first.

That''s a new one to me - the techinical design aspect. It does make sense to do one. I am the only one working on the project, but I still would need one since I plan on doing a modular approach to the game''s development.

I was thinking of licensing one of the following three engines:

PowerRender http://www.egerter.com
VisKit http://www.viskit.com
Panard Vision http://pvision.planet-d.net/

Panard Vision is the only one currently available for free use as long as it is non-commercial. Last year I put out some feelers to see what some of the engines would cost to license commercially, and it was comparable to PR, last year anyways .

I am thinking along the lines of doing the prescribed games to learn the engine - kind of a two birds with one stone approach. A mod would be nice, but currently there are no moddable games out there of this genre.

Speaking of modding, I am looking at emebedding perl into the engine for scripting/modding. Plenty of how-to for doing just that is available from http://www.perl.com/ under the ''Documentation'' section. Perl is a useful ''demicompiled scripting language'' and the tools to do it with are free, for the most part. I''ll definitely need to look at the licensing issues involved with embedding it into my own code.

Thanks a lot!