Quality Defines the Model

Learning Technical Surfacing > Some Common Modeling Basics >

Surface models can be constructed to meet a number of quality levels that depend on the intended purpose of the model and the time allotted for the project. For instance, a model that has to be milled immediately as a 1:4 scaled model will have a different design phase than a model of a digitized master that is intended for a major CAD system (such as CATIA, or Unigraphics).

Surface modeling quality levels

Class A quality (sometimes referred to as Class 1)
Class B quality
Class C quality

Often, quality levels have no fixed definitions as companies often institute their own standards that reflect the demands of their particular industries. Details that are important to surface quality may include the use, or negation of, construction tolerances, highlight standards, trimmed surfaces, radii shape, flange availability, Bezier surfaces, and triangle surfaces.

In general, a surface modeling project can be defined by three questions.

Do the construction tolerances of the continuity between surfaces match the construction tolerances for the required data of the next step (CAD system, milling)?
Do the quality of highlights and curvature combs meet the requirements defined by the designer responsible for the model?
Do the data requirements of an external package match those used to create the model?

When working with Surface, you should begin by setting the construction tolerances. The input construction tolerance levels will depend on the type of system employed to execute the design. If you do not know the construction tolerances at the onset of your project, you can follow one simple rule.

Solid modeling systems (Pro/Engineer, SolidWorks) require small position construction tolerances. Ensure your construction tolerance values work with your solid modeling system.