Automated Approach for Designing Components using Generic and Unitized Parametric Sketches

Abstract

All Major mechanical CAD software products have provided application programming interfaces (APIs) and environments for users to develop customizations and plug-ins to meet their specific requirements. Automation of design methodologies and processes using the available APIs will result in improved productivity of the designers. Typically, during automation of designing a component, one algorithm for a particular shape of the component is implemented in automation programs. In this paper, an automation approach for solid construction using Completely Constrained Generic and Unitized sketches is discussed, that will enable us to implement one algorithm for a family of shapes. Both the types of sketches, i.e., Generic and Unitized sketches are completely constrained and parametric in nature. Generic sketches are those sketches that are constructed to result in more than one shape by making some minor modifications. The required modifications are explained in detail in this paper. These Generic sketches can be either closed or open. Unitized sketches are special cases of Generic sketches that are open. The Unitized sketches cannot be independently used for solid construction. A combination of these Unitized sketches in a sequence can result in a closed profile that can be used for solid constructions. The closed Generic sketches can be independently used for solid constructions. The change in shape of both types of sketches is with respect to the local reference system and the sketches can be positioned in 3d space by defining constraints with respect to the global reference system. This approach can be effectively used in design automation of components that has finite number of shape variations which are driven by design rules. These concepts have been demonstrated in the design of some aircraft structural components.