Some Errata in C.T. Loop:
"Smooth Subdivision Surfaces based on Triangles"

Page 23, para 2:
The new vertices are NOT "the midpoints of of the line segments
 connecting a faces centroid to each of its vertices (Fig.3.1)."
This would create a subdivision mask of

  10 ---- 2
   |      |
   |      |
   2 ---- 2

They are the centroids of the subfaces formed by the face centroid,
a corner vertex, and the two mid-edge points next to the corner.


Page 27, eqn (3.2)
The coefficient of the R-term should be 2/N.


???
In Eqn. 4.7 and 4.8 terms should be V^(l-1) instead of V^l