Modeling

Modeling Build Scan/Digitize Procedural

Build: Creating objects, surfaces, edges, etc… from scratch.

Surfaces created by optical or laser scanner.

Points entered manually by use of a 3D digitizer.

Procedural: Geometry created by user defined equations. Typically used for large “random” scenes (crowds, cityscapes, environmental systems, etc…)

Procedural: “Pixel City”

Types of Models

Parametric

Geometry defined by parameters. Parametric Geometry defined by parameters.

Parameters can control relationships Parametric Parameters can control relationships

Surface

Surface Geometry defined by surfaces Fast, efficient rendering Types: Meshes, NURBS, Polygons

Most common modeling in CAD programs Surface: Mesh Most common modeling in CAD programs

Surfaces defined by 3 sided geometry (Triangles) Surface: Mesh Surfaces defined by 3 sided geometry (Triangles)

Rectangles defined by 2 triangles Surface: Mesh Rectangles defined by 2 triangles

Triangles don’t bend well Surface: Mesh Triangles don’t bend well

“Smoothing” blurs edges, with limitations Surface: Mesh “Smoothing” blurs edges, with limitations

Surfaces defined by Curves Surface: NURBS Surfaces defined by Curves

Surfaces defined by Curves Surface: NURBS Surfaces defined by Curves

Curves defined by Control Points Surface: NURBS Curves defined by Control Points

Changing the curve changes the surface Surface: NURBS Changing the curve changes the surface

Surfaces defined by 4 sided geometry (Rectangles) Surface: Polygon Surfaces defined by 4 sided geometry (Rectangles)

Polygons are easily subdivided. Tools include Extrusions, Bevel, etc… Surface: Polygon Polygons are easily subdivided. Tools include Extrusions, Bevel, etc…

Polygon specific smoothing tools. Surface: Polygon Polygon specific smoothing tools.