WEEK 3: MODELING

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## WEEK 3: MODELING

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**WEEK 3: MODELING**amir@um.edu.my**Modeler Concepts**• Modeler a person who performs the process of creating objects with a 3D software program amir@um.edu.my**There are 4 basic types of modeling systems:**1. Polygonal 2. Spline 3. Patch 4. Parametric amir@um.edu.my**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**It can be difficult to increase its resolution**amir@um.edu.my**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**It uses smooth and natural curves**• Types of splines: 1. B-spline 2. Bezier 3. NURBS amir@um.edu.my**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**Patches can be subdivided to allow more detail**• Can produce very smooth results • Well suited for organic forms modeling amir@um.edu.my**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**Deformations applied to parametric objects can be adjusted**any time amir@um.edu.my**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**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**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**Operands – shapes selected for Boolean operations**• Operations Add, Subtract, Intersection and Split amir@um.edu.my**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**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**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**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**3D Primitives**• Cube • Cylinder • Tube • Sphere • Torus • Cone amir@um.edu.my**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**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**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