Attached Link: Direct Ray Tracing of Smoothed and Displacement Mapped Triangles

Thanks, for the record (and users of the forums search): poser's polygon smoothing looks a lot like this algorithm by Smits/Shirley/Stark (see link). At least it also interpolates the vertices (which means, unlike with Catmull/Clark only the polygons are smoothed, not the vertices). Reyes renderers however usually implement Catmull/Clark not this one (which is not surprising, given that Edwin Catmull (the one with the subdivision) also developed the Reyes algorithm at Pixar :-).