FIT

Feature-based modelling Integration Technology -
Integration of Design by Features and Feature Recognition

The combination of feature-based design and feature recognition is an approach to integrate feature-based modelling in a concurrent engineering environment. This requires a consistent conversion between context dependent semantic (feature-based) views of an product, e.g. design to manufacturing. It is based on the sharing of a semantic model that allows to simultaneously store and manage multiple feature-based representations of an product.

FIT (Feature-based modelling Integration Technology) is a system combining most recent feature-based modelling and reasoning techniques within a homogenous object-oriented development framework.

FIT supports intuitive product design with semantic data. Reasoning techniques based on shape analysis allow to derive different context dependent views of a product. This supports the product design in concurrent engineering environments by integrating the design process with downstream phases of the product development. The main components of FIT are:

• a Design by Feature tool (Figure 1 and Figure 2),
• the Intermediate Modeller, which simultaneously manages the representation of multiple feature-based views (Figure 3)
• and a Feature Recognition and Conversion tool (Figure 4, 5).

Graph of the recognized shape features (figure 4)

Properties

The properties of the FIT system are:

• the access to various toolkits for designing, evaluating and reasoning on semantic product data,
• an object oriented software development environment; the portability is achieved through abstract base classes,
• a full HW/SW independence through abstract system wrappers for graphics, UI, solid modeller and other system services.

System Architecture

FIT is an open and modular system build by the following components:

• an unified object oriented user interface toolkit, which offers semantic 3D direct manipulations, a high level CAD dialogue management toolkit, and a 3D system independent presentation interface,
• an intermediate semantic modelling toolkit including a parametric model and a shape feature object model, which are closely linked,
• a feature-based design modelling toolkit including design process management, libraries for design feature modelling as well as for the management of geometric and engineering constraints,
• a shape feature recognition toolkit which offers geometric reasoning techniques for shape analysis based on boundary data structures,
• an application feature-based conversion toolkit, which provides a specific feature-based model for each application context,
• and an object oriented communication toolkit providing the basic communication techniques.

Application Areas

Possible application areas of the FIT system are mechanical embodiment design and engineering processes, as well as assembly of product parts.

Environment

• SunOS, Solaris, HP-UX
• Solid Modelling Toolkit ACIS
• X/Motif user interface management and UIL
• 3D graphics based on SunPHIGS (SunOS, Solaris) and PEX (Solaris, HP-UX)

Related Projects

• SINFONIA - Feature-based Parametric Design System (IGD)
• Automatic Feature Recognition (IMA)

FIT is a joint cooperation between the Fraunhofer-Institut für Graphische Datenverarbeitung and the Istituto per la Matematica Applicata, C.N.R., which is supported by the EU HCM program.