Reverse Engineering Modeling Methods and Tools: a Survey
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COMPUTER-AIDED DESIGN & APPLICATIONS, 2018 VOL. 15, NO. 3, 443–464 https://doi.org/10.1080/16864360.2017.1397894 Reverse engineering modeling methods and tools: a survey Francesco Buonamici , Monica Carfagni , Rocco Furferi , Lapo Governi , Alessandro Lapini and Yary Volpe University of Florence, Italy ABSTRACT KEYWORDS Reverse Engineering (RE) is a long-term goal of engineering and computer science; it aims at the Reverse engineering; CAD reconstruction of CAD models from measured data by means of 3D mathematical surfaces and geo- reconstruction; constrained metrical features representing the geometry of a physical part. In the last two decades, reviews and fitting; 3D modeling; reverse surveys have occasionally covered this topic, but a systematic dissertation of modeling methods engineering software from a mechanical engineering point of view is still missing. The purpose of this paper is to fill this gap; starting from a general description of the overall RE framework (acquisition, segmentation, clas- sification, fitting), both an up-to-date survey and a categorization of available modeling techniques and tools working on 3D data are provided. The main aspects of various strategies are discussed as well, in order to highlight strengths and weaknesses characterizing different approaches. Moreover, an overview of commercial software for RE is presented, considering both dedicated solutions and packages supplied as add-on with ‘traditional’ CAD systems. Finally, possible improvements to be addressed by the research in the RE field are discussed, outlining potential future trends that are still to be investigated. 1. Introduction an object’s digital model when this is not available is, Widely employed in almost all engineering fields, 3D therefore, beneficial to several situations. Computer Aided Design (CAD) models are among the In case 2D drawings are available, the orthogonal pro- most common medium to convey dimensional and geo- jectionsofthepartcanbeprocessedtoextractuseful metrical information on designed parts, machines, plants geometric data, as described in [38,42,64]; a compre- andsoon.Theincreasingefficiencyoftheproductdevel- hensive review of these techniques is provided in [31]. opment cycle, the reduction of costs of the whole design Whenever 2D representations are not available, the com- process and the possibility of designing and fabricat- mon strategy is 1) to ‘measure’ 3D data directly on the ing complex components (e.g. taking advantage from objectand2)tousetheobtainedinformationtobuilda Computer Aided Engineering and Manufacturing tools digital representation. The present paper focuses on the - CAE/CAM) are some well-known examples of the key- description of approaches dealing with the processing of benefits achieved by using CAD models in engineering acquired 3D data to retrieve a geometric model. practice. The reconstruction of digital models from measured In several situations, unfortunately, the CAD model data has been a long-term goal of engineering and com- of an ‘object’ is not available to the designer, does not puter science in general; this process, usually called even exist, or no longer corresponds to the real geom- ‘Reverse Engineering (RE)’ or ‘CAD reconstruction’, etry of the manufactured object itself. This may be due aims at the generation of 3D mathematical surfaces to various circumstances spanning from manufacturing and geometrical features representing the geometry of related issues (e.g. hand-made objects or post-production a physical part. This is a key problem that finds multi- changes), to wear occurring during a part working life pleapplicationsinengineering,suchasqualitycontrol, (e.g. in case of repairing worn-out parts), or even to the re-engineering of parts and design of custom-fit parts. unavailability of digital data (e.g. in the case of the re- Notbychance,thesetechniqueshaveprovedtobepar- design of obsolete parts manufactured in pre-digital era, ticularly useful in, among others, automotive and med- legal restriction, or trade secrecy). A strategy to retrieve ical fields, where the digitalization of clay models and CONTACT Monica Carfagni monica.carfagni@unifi.it © 2017 CAD Solutions, LLC, http://www.cadanda.com 444 F. BUONAMICI ET AL. human body parts, respectively, are commonly carried means of a case study involving a RE process of a sport out. Most of the tools commonly used by designers are car. implemented within commercial RE software packages, A recent and very accurate survey of surface recon- which combine typical CAD modeling functionalities struction techniques from point clouds, analyzing more with a set of dedicated functions to interact with 3D than 100 works, is provided by Berger et al. in [17]. scanneddata(i.e.pointclouds/mesh).Inthiscase,the The authors highlight advantages and limitations of dif- reconstruction is generally achieved by carrying out a ferent strategies, which are organized according to the time-consuming process, which requires a skilled opera- hypotheses that different algorithms assume in order to tor to guarantee a ready-to-be-used result in downstream reach the solution (e.g. quality of the data, smoothness of applications. the surface, knowledge of the final shape, etc.). Berger’s work, however, is generally concerned with free-form reconstruction and it’s not particularly suitable to the 2. Related work reconstruction of engineering parts, even though there The problem of providing a consistent digital represen- is also a limited number of references to techniques per- tation of a physical object geometry from scanned data forming the fitting of pre-determined shapes. An inter- is still open, especially considering the mechanical engi- esting bird’s eye view of evaluation methods for recon- neer perspective who generally needs methods capable structed surfaces is also provided, proposing tools to of producing results that are: i) accurate and close to the test and compare reconstruction algorithms and their original design of the part; ii) obtained in a limited times- results. pan; iii) easily spendable for the designer’s final need, Most recent contributions to the description of the which usually involves a step in a CAD/CAM/CAE soft- RE state of the art can be identified in [37,9]. A ware [80]. In the last 20 years, considerable efforts have review covering the updated state of art of the entire beendedicatedtoachieveasatisfyingREstrategyand reverse engineering framework, describing its applica- a vast literature of various approaches and methods has tion in manufacturing processes, is presented in [37]. The been produced. authors focus on the description of acquisition systems, A first review of methods dealing with the fitting covering practical aspects, and give an insight of cur- of analytical surfaces to scanned data is provided in rent trends, such as the relation between RE and additive [83]. The authors introduce the problem and the gen- manufacturing. In [9],theauthorspresentadescription eral framework adopted by early methods dealing with of the fundamental aspects of ‘geometric’ RE, provid- CAD reconstruction, focusing on the blending of adjoin- ing interesting contributions on multiple aspects of the ing surfaces. A similar approach is followed in [62], where general RE framework (i.e. conceptual, geometric and the author enlists early techniques dealing with part dig- computational); furthermore, a well-organized descrip- itization, segmentation, and modeling of the final CAD tion of point clouds processing tools, oriented towards model. However, significant improvements have been the recognition of geometric features, is presented. Both lately proposed. the mentioned studies, however, do not focus on the A valid software-oriented review of 3D shape engi- actual generation of surfaces and the modeling strategies neering ispresentedbyChang&Chenin[21], providing that have been presented in the literature to achieve the a description of CAD reconstruction methods particu- reconstruction of a valid CAD model. larly concerned with feature-based parametric methods. The works briefly sketched-out above demonstrate Well-known RE software systems are also assessed by the considerable interest of both the scientific and the means of reconstruction examples to show their strengths industrial communities towards the RE topic but, at the and weaknesses dealing with feature-based modeling. same time, show there is room and usefulness for a Though offering only a partial perspective of the whole survey of CAD reconstruction methods from a prac- RE literature, their work highlights some practical prob- tical engineering perspective, providing an up-to-date lems and needs encountered by designers that are typi- description of tools and methods available to designers; callyoverlookedinseveralreviews. this gap is particularly wide considering the rather poor Following the work and the concepts previously dis- literature concerning the description of state-of-the-art cussed in [21], a concise review of the technical advances reverse modeling strategies. According to these premises, achieved in the RE process is proposed in [4]. The author this paper is meant to help filling this gap, describing outlines the main phases of the typical RE framework but existing RE methods and pinpointing weaknesses and a limited number of methods are covered; a short review advantages from the point of view of a designer deal- of two main commercial software systems (i.e. Geomagic ing with real reconstruction problems. Since a significant Studio v11