Lecture 9: Object-Based Parametric Modeling Flashcards
Object-based Parametric Modeling
Modeling technique that makes objects defined by parameters and rules set up by the designer to determine geometric and non-geometric features
Boundary Representations (B-rep)
Represented shapes as closed, oriented sets of bounded surfaces. Boolean operations (union, intersection, and subtraction) directly interact with the shape.
Constructive Solid Geometry (CSG)
Represented shapes as a set of functions that define the primitive polyhedral. Boolean operations are easy to edit.
B-rep vs. CSG
B-reps shape is the result of the sequence of operations and object arguments. CSG uses parameters & algebraic formulas defining the shape.
Feature-based design parameters
An item in the world generally has multiple subparts with different materials, multiple objects can share parameters. Connected objects behave concurrently and propagate.
Types of relations (3)
- Geometric (distance, angle)
- Descriptive (coincident, parallel)
- Equational (PEDMAS)
Design behavior
How a parametric model responds & adapts to changes in input parameters or objects
Classes
Template definition of the methods and variables in a particular kind of object
Instances
Specific realizations of objects.
Exceptional objects
Do now follow the standard conventions reflected in the
pre-defined classes.