Forming Models Of Plane-And-Cylinder Faceled Bodies From Light Stripes

We use a representation of 3-D bodies derived from that used by Lang and Braid [ 3 ] . Body models are b u i l t up from two kinds of p r i m i t i v e s : the half-space H, defined as the set of points and the i defined as the set of points _ Bodies are represented as boolean combinations of sets r e s u l t i n g from transformations of the (perhaps complemented) p r i m i t i v e s by members of the a f f i n e group of a l l r o t a t i o n s and t r a n s l a t i o n s of threespace. Thus a rod would be represented as an i n t e r section of a transformed c y l i n d e r and two transformed half-spaces.