For questions please refer to the page numbers of the paper
	on my homepage.

	Q--Will Bernstein-Bezier coeficients and control points be constructed
	for the vertex type P which is the centroid of mesh face? 

	A --Yes. Centroids are treated like original points
	    This also answers your question
	Q--about "determining coefficients by analogous
	construction at the other subcell vertex of type P"

	Q -- In Figure 2.3 on page 7, two of five layers of Bernstein-
	Bezier coefficietns are shown. But I can't understand how the other 
	three layers of coefficients can be found. Benjamin ( Hong Kong )

	A -- The construction is symmetric. Thus, if you understand how
	to generate b_{ji} for j \in {0,1}, i\in {0,1,2,3,4}
	you also have the formulas for b_{ij}; this 
	is explained for the case b_{12} and b_{21} on the page.
	Now you are still missing b_{ij} for i,j >= 2.
	However the construction is symmetric with respect to 
	the original point P and the centroid. That is you also have the 
	formulas for b_{ij} for i,j >= 2 (b_{22} is explicitely 
	set to C_i, but you can choose some average of surrounding 
	coefficients as well)

	Q -- In page 7 of your paper, in finding both b12,i and b21,i+1,
	there is 'j' there, I would like to ask what's the meaning oj it and
	how it related to 'i'. c3801040@comp.polyu.edu.hk

	A -- Look at Figure 2.3 directly below the formulas.
	The $i$th neighbor of $P$, $M_i$, has the surrounding 
	panels labelled by $j$ as indicated.

	Q --
	$M_i$, has the surrounding panels labelled by $j$ as indicated in the
	diagram, but how to determine which one of the four sections is Ci1,
	...C14. It's because I can find the general relation between Cij and
	Ci.

	A-- Figure 2.3 indicates that C_i = C_{ij}; the labelling is relative
	to this identity.

	Q -- How to find b14,i? You seems to be not mention in thr paper.

	A -- Well, b_{03,i} is defined. By symmetry of the labelling
	you have the formula for b_{03,i-1} = b_{30,i} and by choosing
	P to be the other vertex of the 4-sided sub-panel, b_{14,i}
	is defined. 

	A --
	1. c does not change meaning
	2. boundaries are a whole chapter by themselves.
	    I usually interpolate the boundary polygon.
	3. I use mathematically positive orientation -- but 
		any consistent orientation will do.
	
	Q -- Also, in the paper, you said that 'there exist a projection of its 
	    vertices into a plane such that none of the projected vertices
	    lies in the convex hull of the other project vertices'
	    Can you explain more on this?
	A -- The statement is precise. If flat, the panels should be convex.