CADDS5 and Parametrics

CADDS5 uses a history-based approach to parametric modeling. It provides solid primitives for CSG modeling. However, these are limited to rectangular prisms, cylinders and spheres. Brep solids can be created from wireframe profiles using the extrude, circular sweep and drive sweep operations. The drive sweep operation sweeps a profile along a wireframe curve to create a solid. It also provides functions for creating surfaces and sewing them together to make solids.

Primitives are also provided for wireframe modeling. These include boxes, circles, ovals, n-sided regular polygons, and round-ended slots. Wireframe profiles can also be created using lines, arcs, and various types of splines. Boolean operations are provided for both solid and wireframe entities.

CADDS5 also provides a standard library of features that can be used to create common geometric features such as screw holes (without threads), pockets, bosses, chamfers, and fillets. It also has several operations for modifying the faces of a solid. They can, for example, be moved, rotated, and have bosses and holes added.

The functions are provided through a toolbar that has various task sets. The task sets group related functions together, and allow many more functions than can be shown on the toolbar at one time. The task sets used for this project include model (solid operations), wireframe (wireframe operations), constraint, and family.

The constraint task set allows variables to be associated with the model parameters. It also allows creation and editing of equations that control the values of the variables. Variables can be either free or fixed. A free variable can have its value changed by a constraint equation, while a fixed variable can not.

The family task set controls the family of parts software. It has four operations: Add Control Parameter, Delete Control Parameter, List Control Parameters, and Visit Family Member. The first two are used to tells CADDS which model variables should be read from the text file when a family member is generated. Adding or deleting a control parameter in a model causes CADDS5 to create a new _tbl file for the part. This file contains the information about each of the family members. CADDS5 reads in the file, and rewrites the file with the proper variables. More information about the format of the text file will be presented later. The third task set lists which variables are under Family of Parts control. The fourth will present a list of family members. When one is selected, the model's control parameters are changed to the values for that member. This can be used to make sure that all of the members of a family will generate without generating them all. If the model regenerates successfully after reading in the values, then the member will generate successfully. It can also be used to diagnose problems if a family member fails to generate. [CV]

Last Modified: Wed Aug 28 14:41:29 EDT 1996