material
ABS as a brickfilm material
Materials
Definition
Acrylonitrile butadiene styrene (ABS) is the injection-moulded plastic that LEGO and other construction-brick systems are made from -- the material a brickfilm animator works in exclusively, since a brick or minifigure part is a manufactured object rather than something sculpted or cast for the production (see brickfilm).
Overview
LEGO switched from cellulose acetate to ABS in 1963, and by the early 1970s every set worldwide was moulded in the new plastic. The company's own account of the change, from process engineer Hans Schiess's development work in Billund, credits ABS with being more stable, more impact-resistant and more colourfast than the material it replaced -- and mouldable to a far finer tolerance, precise enough that LEGO's own moulding philosophy cites an accuracy of roughly 1/200 mm and a rejection rate of about 18 parts per million produced. That tolerance is why a stud from one set still clutches a tube from another decades later: the brick's grip depends on a manufacturing precision most injection-moulded toys never need.
For an animator, that precision cuts both ways. A brick or minifigure never sags, softens under studio heat, or needs an internal armature the way a clay or foam-latex puppet does -- the material itself holds its shape indefinitely, and the stud-and-tube clutch (see tie-down) does the job a magnetic or screw-down rig does for a soft puppet. But ABS does not bend or deform between frames either: a minifigure's entire range of motion lives in its manufactured joints, not in the material. The standard figure carries seven -- a swivelling head, two swivelling arms, two swivelling wrists and two swivelling legs -- with the legs rotating roughly 90 degrees forward and 45 degrees back before the plastic itself resists further. Every pose a brickfilm animator can hold is bounded by that fixed hardware, which is why kitbashing custom parts or printed face decals (see brickfilm) is the usual answer once a shot needs an expression or gesture the stock minifigure cannot make.