Born in March 18, 1928, William Fetter (also known as Bill Fetter) was a well known American graphic designer and was among the first to be considered a pioneer of the field of computer graphics. He was also an art director who was acknowledged as being the first person to have created a figure of the human body as as a 3-Dimensional figure.
Considering how the artistry of computer graphics itself wasn't completely finished in it's research in regards to different methods to create graphics such as Fetter's Boeing Man, I believe it took him. He had used a program he and his colleagues at The Boeing Company had developed to create the figure itself. The initial purpose of the design was to mock-up the position and capability a pilot would have in the cockpit of an aircraft; calculating at what position they might be to be able to reach any materials or instruments that they'd need. In depth, the program he made enabled him to manipulate 3 dimensional prospects of drawings of the human body and morph them into positions they'd uphold.
Considering the particular movements and positions that had to be mapped out by the newly made software, I'd think that, even with the help of multiple collaborators-engineers, designers, programmers, physicists and more, it'd still take while to truly complete this sort of project, considering how new this program was, so approximately a few years were invested into the Boeing Man.
Here's a link to a website where you can find in-depth research into William Fetter's success in the world of computer graphics along with other famous pioneers: http://www.historylink.org/File/20542
Here's also a link with the images of the Boeing Man and the other graphics Fetter had made:
http://dada.compart-bremen.de/item/artwork/240