How does construction-based modeling differ from feature-based modeling and boolean modeling?
Feature-based modeling is linear. A basic solid shape is first created, and features are then added to the first shape(the base feature), creating a composite part. A feature is composed of a geometric shape and a union, subtraction, or intersection operation that combines the shape with the part. As a simple example, a crude T-handled hex drive might be created by defining a cylindrical handle as the base feature, and then the driver portion defined as a protrusion feature by extruding a hexagon and specifying that it be unioned with the cylindrical handle. The key to feature-based modeling is that each new piece of geometry must be immediately combined with an existing part during creation of the new geometry. Boolean modeling is non-linear. The different individual solids used to create a composite model can be created in any order, and then unioned, subtracted, or intersected with each other to form the final composite. With the T-handled hex drive, the cylinder or hex drive would
