I also made contact with a guy in Hungry who has drawn the Tumbler in Maya.  Unfortunately it's not to scale and is really just a shell but still pretty cool.  Here's a look at the car he drew...  which I now have on my computer.  

Im in the process of learning Autodesk Inventor which should allow me to do all the mechanics of the car in a solid state program.  I figure the best way to build a car is start with some detailed plans.  Guys like Bob and Grant are doing a great job without plans but I figure this a long term project and I want have as much as possible drawn up before I start..... I've even got the wifes permission...lol...  So for the moment Im asking Bob and Grant lots of questions and building my plans.  So any help you can give would be  appreciated.

Brad.

www.spidey4fun.ncable.net.au

   I measure stuff, but I don't go into it with a big piece of paper laid out in front of me like a how-to thing. Everything I sculpt (costumes, Alfred, Bale, Hellboy,etc..) I get it in my head which takes a fair amount of time studying. I can tell from just glancing at a drawing of a hoosier tire if that tire was made  up in the drawing, or the dimensions were taken off of the wing sprint dirt tire.

   So, if the 6 tires are not drawn correctly, for example and the rest of the car is based around that, you can expect that the rest of the car, or a fair amount will be off. ala the hot wheels car.

    Here's an example. I've seen a number of tumbler, and one batpod drawing where the hoosiers were drawn with a FLAT center tread. Take any of the internet shots of the hoosier tire, and you'll see that the center of those tires is CURVED. This might indicate that the tire in the drawing was sort of drawn in there without regard to the actual tire itself. An inch off in one area, cascades into INCHES farther down the car. i.e. like a guy holding a pool cue, in one hand and moves his wrist slightly, and the tip of the stick 3ft down has moved inches. I got one, or two spots where in just building the parts with my human hands the back leg next to the gas cap should have been about 1/2" closer to the rear gas cap. I call this, cumlative error. I was lucky it wasn't worse. i.e. if each part is 1/16th of an inch off, then add that up X's 7, or 8 and you got 1/2" off. And you WILL vary at least 1/16th of an inch. Also the precise fitting of each part, or lack of, can throw stuff off as well. My thinking is that anything less than 1" will not be noticable, anything beyond 1" and you will see it, even from a distance.

   I mean, if your thing is to have exactness, then you have to really really know this car, regardless of what drawings are out there because once someone, even the original foam core sculptors of the tumbler start putting their human hands on a sculpture, it is going to deviate from the original blueprints, or gameplan if you will. All these cars are a piece of art more than anything else.