Sweepers and swirling-sweepers are operations for modeling by space deformation. The artist describes a deformation as paths through which tools are moved. The movement of a tool causes a deformation of the working shape along the path of the tool. This is in accordance with a clay modeling metaphor, easy to understand and predict. It is desirable that deformations for modeling are `foldover-free', that is parts of deformed space cannot overlap so that the deformations are reversible. Both sweepers and swirling-sweepers satisfy this criteria. In addition, swirling-sweepers preserve the shape's volume.