Not if you are using Renderman-
Curved Surfaces
The single most important thing a modeler can do to optimize its geometric model for PhotoRealistic RenderMan is use curved surface primitives to model curved surfaces. This is not a trite comment. Historically, modelers and renderers have shared the characteristic of processing polygonal data almost exclusively. Since all curved surfaces were tessellated into polygons by the renderers anyway, it was as efficient (or more efficient) for modelers to control the tessellation by giving the renderer purely polygonal data in the first place. The disadvantages (computation of Phong-interpolated normals, straight-line silhouettes, difficulty of approximating the curve to the right level of detail) were well known, but common to all systems and so were accepted.
PhotoRealistic RenderMan does not fit into this model, however. PhotoRealistic RenderMan accepts and processes curved surfaces directly, and very efficiently. A single sphere primitive will render faster than 30 polygons approximating a sphere, and significantly faster than 1000 polygons approximating a sphere. The curved surface descriptions are more memory efficient (both core and disk) than polygonal approximations of the curves. Moreover, the shading normals of curved surfaces are always correct without resorting to interpolation, its silhouettes are smooth, and the surface is approximated at exactly the right level of detail.
Seven types of quadric primitives (sphere, cylinder, cone, disk, hyperboloid, paraboloid and torus), bicubic patches and non-uniform rational B-spline surfaces are all handled directly by PhotoRealistic RenderMan. Other common modeling surfaces, such as surfaces of revolution, ruled and lofted surfaces, 3-D mathematical functions, etc., are easily converted to curved surface representations, often with no more effort than converting them to polygonal representations.
WAKE UP AND SMELL THE FRICKEN COFEE- Or listen before you speak
