Abstract: An approach for free-form deformation is presented through applying basic functions into the displacement curves.The approach may overcome the constraint in the previous method that a Bézier-shaped displacement reference curve has to be confined into a local hull.As a result,larger deformations with robust computation can be handled in the new approach for any vertex of a given mesh.In the extended curve constraint,the original triangulation and parameterization scheme is replaced with the one based on basic functions by controlling their parameters to generate surface deformations.Meanwhile,a non-uniform deformation technique is introduced by controlling the extension and the magnitude of deformation.