fill3 polygon

I want to highlight an area on a surface plot and fill3 would do the job but I am not sure how to find the 3D points i need. I have a matrix with all the XYZ values as a 3D volume but I need to just find the 'outer' values in order to construct a polygon using fill3(X1,Y1,Z1,C1,X2,Y2,Z2,C2,...)

or perhaps there is a bettr way - subvolume?

Answer 1

[Sean de Wolski]

Will the polygon be convex? If so look at convhull or convhulln to determine the points. If not you'll need to come up with some additional constraints to find the "Outer" points.