Explain Back face detection method ?

Backface Detection method

• Fast and simple object space method
• For identifying the back faces of a polyhedron
• Based ion inside outside test
• Plane parameters A, B, C, D
                    Ax +By+ Cz +D < 0
• Inside point is along the line of sight to the surface
                         V.N = Vz C
• Polygon is back face if C < 0
• Polygon cannot see on any face if C = 0
• Z component value is C <= 0