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Q : What is automatic feature recognition (AFR)?
A : Broadly, automatic feature recognition or AFR involves identifying regions of interest. In the context of CAD/CAM and more specifically the design and manufacturing of mechanical engineering parts, it relates to automatic identification of holes, slots, pockets, bosses, fillets, chamfers, compound holes and other relevant features from Geometric solid models.
Q : How does it help CAD/CAM integration?
A : Many of the design and manufacturing processes adopted in a company are driven by feature information. If the solid models of a part can provide answers to feature-based queries, these processes can be automated. For example, with feature-based information one can hope to automatically generate CNC instructions from CAD models or drive co-ordinate measuring machines for automated inspection. It is very easy to edit feature-based models and create design variations.
Q : Why do I need to use automatic feature recognition (AFR)?
A : Automatic feature recognition technology or AFR is essential for the following reasons:Solid models may not contain feature information. This is the case if models are converted across CAD systems (the feature information is lost during conversion), or if the models were created using older generation CAD systems which did not have feature-based modeling capabilities.

Even if solid models do contain feature information, it may not be appropriate for the task to be performed. For example, models created by a designer would typically contain features created by operations such as sweeps and local modifications; these would not be of direct use to the manufacturing engineer, who would want information about machinable features such as holes, pockets, profiles, etc.

Q : What are the areas where feature recognition technology can be applied?
A :

  • Feature-based editing of imported solid models
  • Selective feature suppression for FEM analysis
  • Automatic process planning and NC code generation
  • Manufacturing cost estimation
  • Automatic inspection
Q : What features are recognized by Geometric’s AFR?
A : Geometric’s AFR can recognize various types of holes, pockets, slots, steps and chamfers.
Q : Can it recognize fillets and chamfers, variable radius fillets and free form fillets?
A : Yes, fillets and chamfers are recognized. The recognized fillets include single and variable radius fillets and spline fillets.
Q : What about compound holes? Can the hole be non-circular (spline profile)?
A : No. Presently, only various types of counter-sunk and counter-bored holes are recognized specifically as compound holes and these have circular cross-section.
Q : What are 2.5D features and 3D features?
A : Features, which can be manufactured on a 3-axis milling machine (with only 2-axes simultaneous control at a time) are termed as 2.5D features. Such features include holes and pockets / steps obtained by sweeping a 2D cross section.Features such as turbine blades, which consist of general spline faces, are termed as 3D features.
Q : Can it recognize all possible features?
A : In parts with 2.5D features, many features will be recognized. However, it is impossible to guarantee recognition of all possible features in all parts.
Q : What kind of input can be made to AFR? What is the output? How do I use the output?
A : AFR accepts a valid solid model as input. Its output is a list of features. API functions and class-based interfaces are provided to interpret these lists and provide feature information to the application program that uses AFR.
Q : What happens if AFR cannot recognize all the features in a body?
A : Features which are not automatically recognized can be interactively identified using the interactive feature recognition facilities provided by AFR.
Q : Can I use the feature information directly?
A : That depends on the application. For CNC code generation, for instance, one can use the feature information directly. However, to enable feature-based editing, it is first necessary to map the feature information provided by AFR onto the CAD system/application’s feature tree.
Q : Does Geometric’s AFR directly support any application?
A : The features recognized by Geometric’s AFR are domain independent. However, Geometric also provides add-on libraries, over and above feature recognition, which generate the design view and manufacturing view variants of the recognized features.
Q : Please outline some typical applications where this technology is being used.
A : This technology is presently being used in applications like:

  • Feature-based editing of imported solid models
  • Feature-based editing during design and feature suppression prior to analysis
  • Feature-based and associative process planning and tool path generation
  • Manufacturing cost estimation
Q : Which companies are currently your customers?
A : For reasons of confidentiality, customer names cannot be disclosed. We would, however, like to state that AFR has been licensed by many leading CAD/CAM software developers in USA, Europe and Asia pacific.
Q : What is the interface available for integration? What support will Geometric provide during integration?
A : AFR provides an API and class-based interface to enable its integration with applications. In addition to answering technical queries to assist integration, Geometric can undertake the integration task itself as a specific project.
Q : How long does it take to integrate AFR with any application?
A : Our experience indicates that the physical integration (after which, feature basic information starts becoming available to the application) and understanding can be achieved in a matter of one week. However, effective use of the feature information requires effort, which is application dependent. Typically it is of the order of six to eight man months.
Q : What are machinable features? How is it different from form features?
A : Form features correspond to features such as pockets, bosses, holes, etc. There exist situations where these features themselves cannot be directly used for machining. For e.g., if there are bosses inside a pocket, the pocket itself is not entirely machinable! Machinable features, on the other hand, represent regions which can be completely removed, and hence can be directly used for generating machining instructions.
Q : What is the difference between the source and object code license? When do I need to license the source code?
A : A source code license offers fully documented source code. An object code license offers compiled binaries, in the form of libraries or dynamically linkable objects that can be integrated with applications. Geometric provides only object code licenses of the feature recognition library.
Q : When is the next version planned and what features will it include?
A : Please write to afr for obtaining the most up-to-date information.