WEEK 3: MODELING

1. WEEK 3: MODELING amir@um.edu.my

2. Modeler Concepts • Modeler a person who performs the process of creating objects with a 3D software program amir@um.edu.my

3. There are 4 basic types of modeling systems: 1. Polygonal 2. Spline 3. Patch 4. Parametric amir@um.edu.my

4. Polygonal Modelers • The oldest type of 3D modeling • Objects are constructed with polylines and polygons • Very useful to create low polygon models –in games amir@um.edu.my

5. It can be difficult to increase its resolution amir@um.edu.my

6. Spline Modelers • Spline  a (usually curved) line, defined by control points. • It’s resolution-independent • Well suited to create complex organic shapes, Example: Human faces, Alien spacecraft, Tyrannosaurs amir@um.edu.my

7. It uses smooth and natural curves • Types of splines: 1. B-spline 2. Bezier 3. NURBS amir@um.edu.my

8. Patch Modelers • Use a network of control points to define and modify the shape of the patch • Control points  control vertices (CVs) – exert a magnet-like influence on the flexible surface of the patch, stretching and tugging it in one direction to another amir@um.edu.my

9. Patches can be subdivided to allow more detail • Can produce very smooth results • Well suited for organic forms modeling amir@um.edu.my

10. Parametric Modelers • Spline-based (Not all spline modelers are parametric) • Parametric modeling features objects that retain their base geometry information (default shape, current size, etc) • This information can still be accessed and changed amir@um.edu.my

11. Deformations applied to parametric objects can be adjusted any time amir@um.edu.my

12. Splines • All splines are similar; they consist of a line/shape; controlled by a polyline or polygon • Three types: B-spline, Bezier spline, and NURBS; Each uses a unique method to control the shape of the spline amir@um.edu.my

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14. Editing 2D Shapes • Easily modified; how a shape is modified depends on whether it’s polygonal or spline-based; some operations are common to both • The basic line and polyline editing operations – moving, adding or deleting line, vertices, or edges amir@um.edu.my

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16. 2D Booleans • Enable us to build onto a shape by combining it with second shape from the first or carve away at a shape by subtracting a second shape from the first • Very useful tools; amir@um.edu.my

17. Operands – shapes selected for Boolean operations • Operations  Add, Subtract, Intersection and Split amir@um.edu.my

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19. Turning 2D Shapes into 3D Objects • Extrusions pushing the 2D shape into the third dimension by giving it a Z-axis depth; useful for creating block-like object/shapes, column, panels, etc amir@um.edu.my

20. Lathing used to create carved cylindrical objects; chair legs and bedposts, A lathe command spins a 2D shape around an axis and extruding it in small steps as it rotates • Lathe  ideal for creating any kind of radial object such as reels, glass, etc amir@um.edu.my

21. Sweeping/lofting A sweep: a single 2D cross-section that is extruded along path • Sweep Types: 1. Open sweep 2. Helical sweep 3. Closed sweep amir@um.edu.my

22. Skinning  similar to open sweep, but here you can use different cross-sectional shapes along the path • It creates a surface to bridge the cross-sections amir@um.edu.my

23. 3D Primitives • Cube • Cylinder • Tube • Sphere • Torus • Cone amir@um.edu.my

24. Transforms • Operations that alter the position, size, or orientation of an object • Basic transforms: 1. Move 2. Rotate 3. Scale 4. Mirror amir@um.edu.my

25. Deforms • Enable you to alter primitives/other objects in subtle or dramatic ways • Types: 1. Bend 2. Skew 3. Twist 4. Squash and Stretch amir@um.edu.my

26. Duplicating Mesh • Objects and shapes can be duplicated via several ways: 1. Copying and Instancing(use clone or copy operation) 2. Arrays (Eg. Basic linear array, Linear array with rotation, linear array with scaling) amir@um.edu.my