According to an example, a processing device may slice a 3D model along a first direction to generate a plurality of layers in parallel planes defined across a second direction and a third direction, in which each of the plurality of layers is composed of respective polygons representing portions of the 3D model. The plurality of layers may be partitioned into a plurality of stacked boxes containing the respective polygons and for each stacked box of the plurality of stacked boxes, the polygons in the stacked box may be assembled into a superset polygon and the superset polygon may be partitioned into bounding shapes. A shape profile of the 3D object may be generated using the bounding shapes.