{'fraction_non_alphanumeric': 0.01773049645390071, 'fraction_numerical': 0.008865248226950355, 'mean_word_length': 5.969135802469136, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Towards a neutral specification of geometric features

The paper concerns the standardised exchange of feature data between CAD systems, or between CAD and downstream application systems. The international standard ISO 10303 (STEP) allows the exchange of CAD models expressed in terms of wireframe, surface or boundary representation solid models. Some published parts of this evolving standard additionally include representations of features suitable for various applications, and other such parts are under development. However, there is no unifying ISO 10303 resource for the general (application-independent) representation of features. Such a resource would enforce consistent feature modelling methodology throughout the standard, and avoid divergent representations that create difficulties in the automation and integration of feature-based applications. A three-level architecture is proposed for the representation of STEP features at an application-independent level. It is compatible with another important ISO standard that represents dimensions and tolerances in terms of the symmetries of feature configurations.