The Protopiper (white paper [PDF]) is a modified tape-gun that extrudes regular, precise lengths of hollow tubing made from packing tape, with which you can prototype room-sized objects at full size to get a sense of the masses and scales involved.
It's a research project from the Hasso Plattner Institute in Potsdam, Germany. The tubes it extrudes have all the strength of cylinders, but can be easily fashioned into joints and hinges.
The Protopiper is structured as an "assembly line" with one mechanism that draws tape off the roll, another that shapes it into a tube and seals it, and third that cuts it at the precise length.
All participants succeeded at creating objects using protopiper.
Figure 31 shows some of them. Throughout the
experiment, participants repeatedly used their bodies and/or
the room for reference. (a) One participant, for example,
created a sunhat directly on the head of another participant.
Also the beach lounge chair was designed to fit the participant's
body. (b) When another team of participants created
a beach volleyball field, sketching at actual scale allowed
them to make sure that the net was placed at a comfortable
height. (c) Yet another team created a beach bar; again by
sketching at actual scale they were able to get all dimensions
right, such as the height of the bar. (d) The shortboard
of this participant, in contrast, did not come out at the right
scale—this, however, might be more indicative of the participant's
(lack of) experience surfing as our lab is located
1000 miles off the next surfable coast.