Plots a convex hull around nodes with index ipart of tree intree (intree can also simply be an Nx3 matrix of XYZ points). Hull patch is offset by XYZ 3-tupel DD and coloured with RGB 3-tupel color. alpha sets the transparency of the patch (by default .2). Option '-2d' restricts the hull patch to two dimensions. HP is the handle to the graphical object. Set options to 'none' to avoid graphical output. Output hull is a structure containing in hull.XY(Z) the coordinates and in the indices to the convex hull (see Matlab function “convhull”).

If the tree is 100% flat 3D convex hull doesn't work. If selected nodes are two draws a straight line. If selected nodes are one plots a point.

Example 1:
convex hull around sub-tree of node #11

>> chull_tree (sample_tree, ...
find (sub_tree (sample_tree, 11)), [0 1 0])   ← RGB for green


Example 2:
2D convex hull around entire tree

>> chull_tree (sample2_tree, ...
[], [], [], 1, ‘-2d’)   ← alpha value 1 for opaque


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