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

disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM Class schedule Monday – – (makmal GIS) Thursday – – 12.50

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

disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM 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 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 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 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. geometric modeling

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

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

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

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

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

disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM animation

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

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

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

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

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

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

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

disediakan oleh Suriati bte Sadimon GMM, FSKSM, UTM 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 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 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. Disadvantages of wire-frame

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

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

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

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

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

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

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