Step 1: 123d Make
1) up to the upper left hand side click File--> Open example-->Rocket. You can also import your own CAD file or browse the online Gallery that has ton's of models to pick from.
2) To toggle the view of your model use your right mouse button, to Zoom in and out use your scroll wheel.
3) Choose a Construction Option- for this project I choose to Radial slices.
Step 2: Entering new Sheet Materials
1) By the tab that says Manufacturing Settings, click on the pencil and this Screen will show up. To add a new Material click on the plus sign below. I have labeled mine Ply wood because I plan on making several projects with this lot of material. for units I kept it in inches and then entered in the following
Length- 96 in
Width - 48 in
Thickness-.72 in- (even though they say its 3/4 in ply its almost always a bit under)
2) Enter in your desired size, because of the way the model was created I wanted the bottom piece that held everything together to be one solid piece. So I started at 8 feet and tapped my way down to 6.2 before the warning sign on the bottom right of screen turned off saying that the piece would fit on one cut.
This is also a good way to figure how many sheets you have vs need. If size is not as important to you as amount of sheet material than you can use this to design down to the ideal size for the amount of lumber you have.
Step 3: Assembly
1) click on Assembly Steps- and use the scroll bar to figure out how you would assemble this beast.
2) when finished go ahead and choose "Get Plans" here you will sign in with your 123d login and then save out as .eps or svg. Both are great and open in multiple CAM software packages.
Step 4: Finishing up.
My final version was done by some friends with a giant laser cutter, which brings me to good point, ... Make good friends.
Enjoy this Project, I did. )