Could be wrong here, but I think most uses of raytracing like this limit it to shading and use traditional method for shadows. (Shading being the way that light

Could be wrong here, but I think most uses of raytracing like this limit it to shading and use traditional method for shadows. (Shading being the way that light "appears" on surfaces, shadows determining roughly how well illuminated a surface is. In theory you could use raytracing for both, but there may be limitations?)