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Graphics modeling

Graphics modeling. Class schedule. Monday – 11.00 – 12.50 (makmal GIS) Thursday – 12.00 – 12.50. review. What have you learnt in ASAS GRAFIK KOMPUTER?. What is geometric modeling?. Collection of methods used to define the shape and other geometric characteristics of an object.

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Graphics modeling

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  1. Graphics modeling disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  2. Class schedule • Monday – 11.00 – 12.50 (makmal GIS) • Thursday – 12.00 – 12.50 disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  3. review • What have you learnt in ASAS GRAFIK KOMPUTER?. disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  4. What is geometric modeling? • Collection of methods used to define the shape and other geometric characteristics of an object. • To construct a precise mathematical description of the shape of a real object or to simulate some process. • Embraces area – computational geometry disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  5. What is geometric modeling? • special case of mathematical modeling • the visual features are important. • geometric model - physical object. • non-geometric model – physical process e.g economic disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  6. Geometric data • To make pictures/ design new things need a computer representation of objects. • Need to represent • Shape • Appearance (color, shininess etc) • Material properties (density, stiffness etc) disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  7. geometric modeling • Geometric data representation • Compute a mathematical approximation of the physical shape of an object • Algorithms for manipulating geometry • Manipulate the variables defining the shape until we meet the objective. • Geometry creation • Interactive. • Automatic creation. disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  8. Application • Computer Aided Design/ engineering (CAD/CAE) • Entertainment • Special effects • Animation • games • Scientific visualization • Education, information, advertising disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  9. CAD/CAE • Stages • Conceptual design • Mechanical design • Simulation • Production • Geometric data need to be shared disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  10. CAD/CAE • Conceptual design disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  11. CAD/CAE • mechanical design disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  12. CAD/CAE • simulation disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  13. Special effect • Merge real and virtual objects • Create virtual scenes indistinguishable from reality disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  14. animation disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  15. games • Adventure - interactive disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  16. visualization medical geographical Bio-geometric disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  17. Requirement : Visualization • Space efficiency • Generality • Precision • Support fast algorithms disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  18. Requirement : CAD/CAE • Precision is very important • Integrate additional data • Smooth surfaces • Algorithms for thermal/stress simulation, tool path generation etc. • Automatic acquisition for reverse engineering. disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  19. Requirement : animation and special effects • Generality – all kinds of natural and artificial objects • Flexibility – let animator make choices • Support high-quality rendering • “semiautomatic” acquisition. disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  20. Requirements : games and VR • Interactive games • Support for interactive rendering crucial • Models should be small • Easy to animate • Procedural generation disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  21. Existing software • 3DS Max • Maya • Rhino disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  22. Applicable mathematical technique • Linear algebra • Vectors • Matrix methods • Determinants • Set theory • Polynomial interpolation • Numerical approximation disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  23. Geometric modeling scheme • Wire-frame model • Surface model • Solid model disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  24. Wire-frame model • The shape of the object is defined by a collection of points (vertices) and a set of edges. • Edges – line or curved connects pair of points • Conventional Approach - Place the geometry entirely in the data structure. •  Another Approach - Procedural Approach disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  25. Wire-frame model • Example : tetrahedron disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  26. Disadvantages of wire-frame • Tend to be not realistic • Ambiguity • complex model difficult to interpret. What does this object look like? disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  27. Disadvantages of wire-frame Which object does the previous wire-frame represent? The use of shading and hidden surface removal technique can improve the rendition. disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  28. Disadvantages of wire-frame • Does not allow for use of photo realistic rendering tools. *(some software capable of hidden line removal on limited basis). • No ability to determine computationally information on mass properties (e.g volume, mass, moment etc) and line of intersect between two faces of intersecting models. • No guarantee that the model definition is correct, complete or manufacturable. disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  29. Advantages of wire-frame • Easy to construct • Most economical in term of time and memory requirement. • Used to model solid object. • Often used for previewing objects in an interactive scenario. disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  30. Surface model • An area bounded by an identifiable perimeter. • In Computer Graphics, is an area within which every position is defined by mathematical method. disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  31. Surface model disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  32. Surface model Surface may be: – Planar – Cylindrical/conic – Sculptured or freeform in shape disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  33. Surface model • To overcome ambiguity in wire-frame model • used for the generation of visually • realistic images through techniques • such as • rendering • hidden edge removal. disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  34. Surface model • Does not represent internal features of • the model, no sense of volume. • •Models of limited value for volumetric and mass property analysis. disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  35. Solid model • Most complex • Complete representation • unambiguous description • Appropriate for the world of engineering objects disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  36. Solid model disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

  37. Step from geometric to program • Geometry algebra  algorithm program representation • Symbolic • Numerical • approximation disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM

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