{"responseHeader":{"status":0,"QTime":13,"params":{"q":"{!q.op=AND}id:\"107199\"","hl":"true","hl.simple.post":"","hl.fragsize":"5000","fq":"!embargo_tdt:[NOW TO *]","hl.fl":"ocr_t","hl.method":"unified","wt":"json","hl.simple.pre":""}},"response":{"numFound":1,"start":0,"docs":[{"modified_tdt":"2016-11-18T00:00:00Z","thumb_s":"/e4/a1/e4a1225dd6145593d746de467310ae3602d49671.jpg","oldid_t":"compsci 15312","setname_s":"ir_computersa","file_s":"/f1/0a/f10a3b7ee8d58b57880a962dfd9dec8c5f64b566.pdf","title_t":"Page 3","ocr_t":"1. Introduction One of the classic problems in computer graphics [4,5] is the _del1in9 ,and Tehdfring. ,of surf.ees ;n ttwee-dimensional space.. .the. ocall. ed sculpture surfaces,•.. A fundamental reason for the considerable amount of research carried out in the 1960's was the ambiguity of conven-- . tional engineering drawings when applied to arbitrary surfaces. It is irnpossi.ble, -in general, 'to define doUbly-curved sur-faces in terms of a finite nUmber of planar line drawings (although particular doubly-curved surf_ces such as ellipsoids, .surfaces ·of revolution, etc. can be defined unl:quily ''in tenDS tJf ''1 me- :Vt'awtAgs->; -the -prabl em ;may be- ·.p.ve\"\"Rre- ;by_-:the use of, 'analYtic model's for ,surfac.e·s. Here the pioneer work by Coons and thers is -wel1 ... know,n. It is>now cORlllOn to. represent a 'surface in tenns of a -mathematical model (usually_ analytic equati-ons), and to use the model to derive ' drawings of various fonns. The ability rapidly to generate complex drawings from a computer model and to display these drawings- on a c.r.t. or plotter. has proved of great use in practice. Neve·rtheless, it is- the contention of the ,a.uthor that the methods used to display arbitrary surfaces are still ambiguous, uninformative, and imprecise. In this paper e survey some of the methods commonly used, hi.ghlighting their drawbacks, and suggest more meaningful methods which exploit recent advances in- -raster !JlI'apfrfcs' tecnno.logy. In particular we concentrate on the pre-sentati-on 'of urfa;ceSc 'fo;r engineeri,ng design and manufacture, rather than for animation, simulation, etc. 2. Conventional Techniques - Line Drawings __ . We shall consider rendering of surfaces tn the context of-'c.r.t. Elisplays, caligraphic or raster, since mos,t of the teetu)i'ques\".e\" app1,tcalUe to other devices, such as plotters, in some, fonn or other.- Befor.e 00·in9 so. two methods of display must be mentio,ned: clynam:ic dislJrl&'j 8lflct Hl'td'model generation. With the availability of high--per-ftJ...dw d.,_,;ay£.\\f;lfff.","restricted_i":0,"id":107199,"created_tdt":"2016-11-18T00:00:00Z","format_t":"application/pdf","parent_i":107216,"_version_":1642982404647813121}]},"highlighting":{"107199":{"ocr_t":[]}}}