Polar to Rectangular This filter (and its reciprocal twin, Rectangular to Polar) has its roots in Photoshop. It treats your artwork as though it was drawn in polar coordinates (that is, being specified by an angle and some distance from a center), and converts it back to rectangular, or conventional x-y, coordinates. The effect you get will depend, of course, on your artwork. Polar to rectangular can generate some fascinating circular effects, including circular grids made instantly from square ones. Experiment!