document: Evaluation of existing and new feature recognition algorithms . 1 . Theory and implementation This is the first of two papers evaluating the performance of general-purpose feature detection techniques for geometric models . In this paper , six different methods are described to identify sets of faces that bound depression and protrusion faces . Each algorithm has been implemented and tested on eight components from the National Design Repository . The algorithms studied include previously published general-purpose feature detection algorithms such as the single-face inner-loop and concavity techniques . Others are improvements to existing algorithms such as extensions of the two-dimensional convex hull method to handle curved faces as well as protrusions . Lastly , new algorithms based on the three-dimensional convex hull , minimum concave , visible and multiple-face inner-loop face sets are described
doc_bio_tags: O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O B I I O O O O B I O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O B I O O O O O O O O O
extractive_keyphrases: feature recognition algorithms geometric models sets of faces protrusion faces national design repository curved faces minimum concave
abstractive_keyphrases: general-purpose feature detection techniques depression faces single-face inner-loop technique concavity technique two-dimensional convex hull method three-dimensional convex hull cad/cam software geometric reasoning algorithms visible inner-loop face sets multiple-face inner-loop face sets