A recursive subdivision algorithm for piecewise circular spline

We present an algorithm for generating a piecewise G(1) circular spline cur ve from an arbitrary given control polygon. For every corner a circular bia rc is generated with each piece being parameterized by its are length. This is the first subdivision scheme that produces a piecewise biarc curve that can interpolate an arbitrary set of points. It is easily adopted in a recu rsive subdivision surface scheme to generate surfaces with circular boundar ies with pieces parameterized by are length, a property not previously avai lable. As an application, a modified version of Doo-Sabin subdivision algor ithm is outlined making it possible to blend a subdivision surface with oth er surfaces having circular boundaries such as cylinders.