Curved structures are used in buildings and may be integrated with photovoltaic modules. Self-shading occurs in non-flat (curved) surface collectors resulting in non-uniform distribution of the direct beam, diffuse and reflected incident solar radiation along the curved surface. The incident solar radiation therefore affects adversely the output of the electrical generated energy. The total annual incident radiation is independent of the orientation of the convex surface. The present study develops analytical expressions for self-shading and expressions for the incident solar radiation on a general convex surface.