The paper introduces an algorithm for creating smooth spline surfaces over control triangular meshes capable of outlining arbitrary free-form surfaces with or without boundary. The resulting surface has a degree 4 parametric polynomial representation and is represented as a network of tangent plane continuous triangular Bézier patches. The approximation of resulting surface to mesh is controlled by a blend ratio; when the blend ratio is zero, surfaces interpolate meshes. The algorithm is a local method, simple, efficient and fit for appearance design.