Space deformation is a very important tool in computer animation and shape design. In this paper, the authors propose a new general deformation model containing point, line, surface and volume constraints based on the special distribution of the potential function of a generalized metaball. The user specifies a series of constraints, the effective radius and displacement of each constraint, then the deformation model creates a generalized metaball for each constraint according to each specified constraint and its effective radius. The generalized metaball produces a potential function centered on the constraint, it drops from 1 on the constraint to 0 on the effective radius. This deformation model operates on the whole space and is independent of the underlining representation of the object to be deformed. The deformation can be finely controlled by adjusting the parameters of the generalized metaballs. Experiments show this general deformation model is efficient and can deal with line, surface and volume constrains which are difficult for the traditional deformation models.