This paper describes the construction of 3D binairy images using one camera and a rotating object or a moving camera on a robotarm. Two methods are combined. First polygonal convex hulls of object cross-sections are found with the volumetric approach. Then a stereovision method is applied to get hold of the non-convex part of the cross-sections. The binairy 3D image is represented by a stack of polygons. An example is given.