GanosBase introduces three data models for mesh modeling, built on the Open Geospatial Consortium (OGC) Simple Features (SF) standards. Each model represents a 3D polyhedron differently — by index references, by sequential strips, or by a fan radiating from a fixed point.
IndexSurface
IndexSurface represents a polyhedron by referencing vertex positions through indexes, so each triangular face is defined by index numbers rather than repeated coordinates.
The following figure shows a polyhedron.
For a polyhedron with five vertices (p1, p2, p3, p4, p5), the faces are expressed as index triplets: (1, 2, 3), (2, 4, 3), and (4, 5, 3). The vertex coordinates are stored once and referenced by index, making this model efficient when multiple faces share the same vertices.
TriangleStrip
TriangleStrip represents a polyhedron as a sequential strip of triangles, where each new triangle shares an edge with the previous one.
The following figure shows a polyhedron.
For a polyhedron with five vertices (p1, p2, p3, p4, p5), the three triangular faces are (p1, p2, p3), (p2, p3, p4), and (p3, p4, p5). Each face advances the strip by one vertex, reusing the two vertices from the previous triangle.
TriangleFan
TriangleFan represents a polyhedron as a fan of triangles anchored at a single central vertex, where all triangles share the first vertex.
The following figure shows a polyhedron.
For a polyhedron with five vertices (p1, p2, p3, p4, p5), the three triangular faces are (p1, p2, p3), (p1, p3, p4), and (p1, p4, p5). The first vertex (p1) is the anchor point shared by every face in the fan.