Systems and methods for performing shading operations of a three-dimensional model, such as a three-dimensional model of a geographic area, are provided. According to aspects of the present disclosure, shading operations can be performed based on a curvature of the polygon mesh such that smooth surfaces still appear smooth after shading and such that sharp edges still appear sharp after shading. In particular, a curvature-driven normal is used for shading operations that takes into account the local curvature of the polygon mesh. A curvature factor can be obtained for each vertex in the polygon mesh. The curvature factor for each vertex can be a scalar value that describes the degree of local curvature in the mesh polygons connected at the vertex. The curvature-driven normal for each fragment can be determined based on the curvature factors associated with the vertices in the polygon mesh.