Object Description

1. Object Description

2. Figure Modelling

3. Mathematical Methods (Splines)

4. Local Control Property

7. The Problem A large amount of excellent work is carried out in the area of Computer Graphics BUT methods are not compatible

8. Description of objects Surface - skin of the object

9. Rectangular Patches

10. Rectangular Patches • simple theory • the data structure is equivalent to a rectangular array • continuity is easy to handle • the two-variable problem is reduced to two single variable problems

11. Unfortunately

13. Standardising Surface Description #Vertices x1 y1 z1 x2 y2 z2 x3 y3 z3 x4 y4 z4 x5 y5 z5 x6 y6 z6 x7 y7 z7 x8 y8 z8 #Faces 1 2 4 3 5 6 8 7 1 2 6 5 3 4 8 7 1 3 7 5 2 4 8 6

14. Non Rectangular Patches #Faces 1 2 3 4 5 6 7 8

16. # Vertices vx1y1z1 vx2y2z2 v x3y3z3 vx4y4z4 v x5y5z5 vx6y6z6 # Faces f 1 2 4 3 f 5 6 8 7 f 1 2 6 5 # More Vertices v x7y7z7 vx8y8z8 # More Faces f 3 4 8 7 f 1 3 7 5 f 2 4 8 6 The Data-File

17. The Data Structure float vertices[MAX_VERTICES][3]; int faces[MAX_FACES][MAX_VERTICES_IN_FACE + 1];