"Art of Illusion" (

"Hash" spline patches allow you to build complex, organic shapes and animations
using spline curves. These patches are used in commercial
"Animated Master" 3D Modeller by
Martin D. Hash (see also
A complete
algorithm for real-time spline-based character animation).
The same spline patches are used in
"sPatch"
(Ver 1.5, Copyright 1996-1998 by |

"sPatch" uses meshes made only of 3 or 4 spline segments. But "Animated Master" spline engine can use hooks and 5-splines patches too. Therefore when I try to export some of Eggington productions models, I get "broken horse". You see the 5-splines hole in the figure. Moreover as "sPatch" uses (IMHO) degenerate 3-splines patches, we get folded defects for these patches too in the left picture and when I try to repair the 5-splines hole by one more line (i.e. if I make 4-splines and 3-splines patches). I hope hooks and 5-splines patches can be implemented in "HamaPatch" too.

All verteses can be stored as an array, then indexed face set (IFS) of
triangular spline patches (and barycentric coordinates) can be used to
represent an object.
The VRML viewer "Cortona" supports "SplineFaceSet" VRML extension node similar
to the standard IFS. "The method of spline representation of geometry objects
is based on three-cubic spline interpolation, using incoming polygonal data
(control vertices)." See "spline tetrahedron" and
"spline cube" demos.
But I don't know how to combine these patches
C smoothly and if there is a handy method to build all the
heap of points in an authoring tool. Are triangular patches useful for
scanned objects?
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