This article discusses the application of the visioplasticity method to the evaluation of large plastic strains such as those occurring in metalforming. Although this method can be used for any mode of deformation, its application to plane-strain deformation is treated here. The distortion of a quadrilateral element of a grid is tracked to compute strains during deformation. In each case any two lines of the quadrilateral can be used (length before and after deformation and direction cosines before deformation) to determine strains in the element. The method has been verified by application to basic cases of deformation such as uniaxial compression, tension, pure shear, and rotation of elements. The effect of choice of lines upon the results of strain calculation is also discussed.