This paper explores shape from contour for acquiring 3-D graphics mode
ls. In this method, a continuous sequence of images is taken as an obj
ect rotates. A smooth convex shape can be estimated instantaneously fr
om its contour and by the first derivative of contour movement (trace
of contour, or contour distribution with time). We also analyze shapes
that do not satisfy the conditions of smoothness and visibility, whic
h are indispensable for modeling an object. A region that does not exp
ose as contour yields a nonsmoothness in the tracked contour movement.
We can thus detect such a region by contour distribution filtering an
d extract its accurate location by computing the left and right deriva
tives of the distribution. This has not been studied previously. These
unknown regions are obtained for further investigation using other vi
sual cues. A general approach for building a geometrical object model
using contours is then described. The entire process from silhouettes
to a 3-D model is based on local computation; this is promising for pr
oducing shapes in real time. Our direct goal is to establish 3-D graph
ics models of human races for the growing needs of visual communicatio
ns. We have obtained some good results.