As background, I built a CNC machine in 2008 and have gradually taught myself the ins and outs of using it over the past several years. I've gone from simple two-dimensional projects to bas relief to full 3D. It has a cuttable area of 36" x 24" x 5" and lands squarely in the camp of hobbyist CNC. Additionally, I am well-versed in a number of graphics and 3D modeling packages. To duplicate the results here, you'd need access to a similar CNC machine and be reasonably good with 3D software tools.
The subject of this instructable is actually the result of a modeling tutorial titled 3D Modeling in Silo: The Official Guide by Antony Ward, David Randall and Nevercenter. The chapters in that book take you through a character modeling exercise in which you create this figure using a program called Silo 3D. This is exactly what I did and the outcome is a compelling blond hovering in a rocket pack with a pistol in her left hand.
It was at the end of this book that I felt I wanted something more for my efforts. I figured that buildng her as a life-size sculpture would make a kick-ass exhibit and expand my abilities along the way.
Step 1: Assemble your tools
Silo 3D is the modeling software and, of course, the book I mentioned if you're looking to create the same exact character. Alternatively, you can use other programs such as Sculptris, 3D Studio Max, Modo, ZBrush, Blender, etc. There are a lot of choices out there along a whole range of price points. Silo is relatively inexpensive and it, along with the book, will cost under $200.00 total.
In addition to the modeling software, you'll need some software tools (generally known as CAM or Computer Aided Manufacturing) to prepare the model for machining. I own a program called Cut 3D made by Vectric Software and it is the application that allows me to position the pieces, set up the tool paths and create the G-Code that will ultimately drive the CNC mill. Again, there are other programs that let you do that, but I'll discuss the one that I use.
Next, you'll need something to make her out of. Since I was going to create a life-size piece, I wanted the material to be as light as possible. Inexpensive is nice too. I chose rigid foam insulation from a home improvement store. The product is Dow Foamular and it is a pink foam available (around me, anyway) in 4'x8' sheets up to 2" thick. The 2" pieces cost about $25 each and I think I went through about 6 pieces. I made some mistakes along the way, so it can probably be done with only 4 sheets.
I knew I would need something to tie her all together (a skeleton or armature) and for this I chose half-inch PVC plumbing pipe which is plentiful, inexpensive and easy to work with.
I'm sure some people are cringing at the thought of creating a sculpture out of foam. While it is light and inexpensive, the surface is not exactly smooth and it can be easily gouged with just a fingernail. This problem is solved by topcoating it with what essentially is a liquid plastic. A product called Styrospray 1000 from Industrial Polymers (http://www.industrialpolymers.com) is a two-part liquid plastic that can be brushed on as well as sprayed. It's about $120 for a 2-gallon kit and I probably used about a gallon on this project. Unless you have access to a supplied air respirator, I'd recommend brushing it versus spraying.
Other things you'll need are drywall repair compound (I used Spackle), epoxy modeling putty (Magic Sculpt), plywood for the stand and paint.