Coordinate values that always refer back to the origin.
Coordinate values that refer back to a previously defined point or feature.
"Stationary" or "Fixed", never changes position or orientation relative to the model.
Coordinate system defined by the designer or CAD system. May be located and oriented anywhere and in any direction within the World Coordinate System
Primitives are the building blocks used to create drawings and CAD models
No size, shape, width, height, or depth
All possible positions of a point
Length and direction, no thickness
Generated by point moving in constantly changing direction
Curves can be generated by intersecting surfaces
Various order polynomials fit through every point
Splined: different polynomials used for different sections
Constraints define the geometry through geometrical relationships
Implicit: software assumes constraints exist in a sketch
Explicit: user must define the constraints
Conditions are similar to constraints but they are not enforced. Conditions are simply the geometric (or kinematic) state of the feature.
Constraints remain enforced until the designer releases them. Conditions are simply the state of the feature at a given moment or location.