INTERNATIONAL JOURNAL OF COMPUTER APPLICATION ISSUE2, VOLUME 1 (FEBRUARY 2012)
ISSN: 2250-1797
Parametric Jewelry Modeling in AutoCAD using VBA Vishal Gulati #1 #1Department of Mechanical Engineering, GJ-University of Science and Technology, Hisar, India
[email protected]
Abstract This work implements parametric jewelry modeling in Visual Basic Applications (VBA) programming environment that runs simultaneously with AutoCAD and provides programmable control of AutoCAD through the ActiveX Automation interface. Jewelry modeling with CAD system in a programming environment represents the jewelry design steps which are programmed to be executed automatically. In particular, this paper presents a CAD paradigm that makes the technical contribution of developing a parametric jewelry modeler for designing traditional carved pendants. Keywords- Parametric, CAD, Jewelry, Carved Pendants #1 Corresponding Author
1. Introduction Parametric modeling in CAD refers to the use of numeric parameters for defining and manipulating solid models. The great virtue of parametric modeling is the ease of altering the model with a set of parameters. Parametric modeling is carried out with two approaches. Firstly, with the CAD system having parametric modeling capabilities which allows the user to update or modify the model with new parameters by interacting him with the CAD system during the modeling process. Secondly, with the CAD system that provides interface via Application Programming Interface (API), which enables the user to interact with the model environment for improving design automation. It is difficult to perform parametric modeling of irregular shaped objects (like jewelry) with the parametric CAD systems. It is not truly impossible to apply parametric modeling to irregular objects, but many steps may be required, and the resulting set of modeling steps and parameters becomes more and more difficult to understand, much less modify, because each step is dependent on every prior step. In order to carry out parametric jewelry modeling, a specific algorithm is required that can be programmed to be executed automatically. Such an algorithm can be generated with some programming language which interacts with CAD system through an interface. This programmatic approach can utilize the predefined native geometrical CAD entities (point, line, circle, spline, etc.) and operations (extrusion, revolution, union, intersection, subtraction, offsetting, etc.) together with the specific algorithm programmatically. Such a programmatic approach reveals design automation by integrating and customizing CAD system with a programming language through an API. In this continuation, this work implements parametric jewelry modeling in Visual Basic Applications (VBA) programming environment that runs simultaneously with AutoCAD and provides programmable control of AutoCAD through the ActiveX Automation interface.Jewelry modeling with CAD system in a programming environment represents the jewelry design steps which are programmed to be executed automatically. This means that each different piece of jewelry would not have to be created basically from the beginning. This gives the user the benefit of repeatability, handling errors, requesting user input and accessing databases.
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Parametric concept of jewelry modeling is the jewelry designing process in which the user participates through the definition of parameters and his/her interaction’s directly turns into a 3-D solid jewelry model. Parametric modeling is incorporated to capture the designer’s intent, to get the variation in jewelry designs and to support customized jewelry design process. Moreover, this parametric jewelry modeling concept is towards the elimination of the formal jewelry designer by providing the design tool in the hand of user for generating jewelry of his/her choice.
2. Literature Most of commercial CAD systems available for the jewelry modeling are parametric [1-4]. But in majority of these systems, designing is performed manually using various tools and usually the design steps cannot be programmed to be executed automatically. Some parametric modelers have been developed where the jewelry design is expressed by a set of parameters and constraints and the user’s participation in the design process is through the dentition of the parameter values. ByzantineCAD has been developed for the designing of pierced medieval Byzantine jewelry [56]. A Feature-based CAD System for Reconstructing Traditional Filigree Jewelry has also been developed [7]. A parametric voxel based approach has been presented to produce for stretchformed and carved jewelry [8-9]. A jewelry modeler has been created for designing fret-worked and carved jewelry bangles [10]. A feature based CAD approach to re-engineering jewelry has been presented [11-12]. An aesthetic driven approach to jewelry design has also been presented which proposes a CAD tool to automate jewelry art form generator [13].
3. Implementation This work has been implemented in AutoCAD under the ActiveX Automation interface and VBA programming environment. AutoCAD is customized for jewelry design automation through ActiveX Automation interface which manipulates AutoCAD programmatically using VBA. This coupling of ActiveX Automation and VBA manipulates AutoCAD objects that encapsulate AutoCAD entities, data, and commands. Through ActiveX Automation, AutoCAD exposes programmable objects (lines, circle, arcs, copy, erase, move, mirror, rotate, text, dimensions, line types, dimension styles, layers, groups, blocks, view, viewport, etc.) described by the AutoCAD Object Model that can be created, edited, and manipulated by VBA programming environment. VBA has its own set of objects, keywords, constants, and so forth that provide program flow, control, debugging, and execution. It runs in the same process space as AutoCAD. It sends messages to AutoCAD by the ActiveX Automation interface which establishes communication with AutoCAD objects.
4. A CAD Paradigm In particular, this paper presents a CAD paradigm that makes the technical contribution of developing a parametric jewelry modeler for designing traditional carved pendants (Fig. 1). A jewelry design is expressed by a set of parameters. The modeler generates new jewelry designs by changing the parameters. The user participates in the modeling process with selection of a voxel from the library of pre-defined voxels (Fig. 2). The voxel library is an open-ended catalogue to which new voxels can be added. The possible variations in jewelry designs depend upon the richness of voxels in the library. The voxel element is described with a signature P/L/T/α/X/Y/R, where P stands for maximum number of valid points, L for size, T for thickness and α for inclination of side surface of voxel element, X and Y for variants and R for radius of center hole. The voxel signature represents the modeling parameters (Fig. 3).
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Fig. 1 Traditional carved pendants
Fig. 2 Pre-defined voxel elements Page 160
Fig. 3 Voxel parameters
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During the jewelry modeling process, a parametric voxel is generated in XY plane; its multiple copies are conFig.d in rows and columns (R and C); an array of conFig.d element(s) is created in XY plane about the Z axis passing through any one of the valid points (Pt) for an angle (θ) and a number (N); and joined into a type of jewelry (pendant). CAD models of such carved jewelry pendants are shown in the Fig. 4. By putting the modeling parameters through a user interface (Fig. 5), jewelry designs are rendered and further submitted to RP machine for the production of master pieces (Fig. 6) [14].
Fig. 4 Rendered parametric carved pendants Page 162
Fig. 5 Modeling parameters through user interface
Fig. 6 CAD and RP model
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5. Concluding Remarks Parametric jewelry modeling is quite unique concept. Jewelry models, which are created by using the parametric design concept, show large variations in the designs. The work customizes the features of AutoCAD under a programming environment (VBA) in order to use its graphics capabilities. AutoCAD is capable of creating STL file, which supports diverse integrated manufacturing. The proposed approach has far reaching potential in enhancing the ornamental products especially jewelry.
References [1] J JewelCAD, http://www.jcadcam.com, Jewelry CAD/CAM Ltd. [2] ArtCAM Jewel Smith, http://www.artcamjewelsmith.com, Delcam plc. [3] TechGems 3.0, http://www.techjewel.com, TechJewel. [4] JewelSpace, http://www.jewelspace.net, Caligory Software. [5] Stamati V. and Fudas, I., 2005, A Parametric Feature Based CAD System for Reproducing Traditional Pierced Jewelry, Computer Aided Design, Vol. 4, No. 37, pp. 431-449. [6] Stamati V., Fudas I., Theodoridou, S., Edipidi C. and Avramidis D., 2004, Using Poxels for Reproducing Traditional Byzantine Jewelry, Computer Graphics International 2004, Crete, Greece, June 16-19. [7] Stamati V., Antonopoulos G., Azariadis Ph.and Fudos I., 2011, ReJCAD: A Feature-based CAD System for Reconstructing Traditional Filigree Jewelry, Computer Aided Design (Available online.) [8] Gulati V. and Tandon P., 2007, A Parametric Voxel Oriented CAD Paradigm to Produce Forming Components for Stretch- Formed Jewelry, Computer Aided Design & Applications, Vol. 4, No. 1-4, pp.137-145. [9] Gulati V., Singh H. and Tandon P., 2008, A Parametric Voxel Based Unified Modeler for Creating Carved Jewelry, Computer Aided Design & Applications, Vol. 5, No. 6, pp. 811-821. [10] Gulati V., Tandon P and Singh H., 2010, A Jewelry Modeler for the Fret-worked Bangles, International Journal of Computer Applications, Vol. 2, No. 2, pp. 76-80. [11] Stamati V. and Fudas, I., 2005, A Feature-Based CAD Approach to Jewelry Re-Engineering, Computer-Aided Design & Applications, Vol. 2, Nos. 1-6, pp. 1-9. [12] Fudos I., 2006, CAD/CAM Methods for Reverse Engineering: A Case Study of Reengineering Jewelry, Computer-Aided Design & Applications, Vol. 3, No 6, pp. 683-700. [13] Wannarumon S., 2010, An Aesthetic Driven approach to Jewelry Design, Computer-Aided Design & Applications, Vol. 7, No. 4, pp. 489-503. [14] Wannarumon S. and Bohez E. L. J., 2004, Rapid Prototyping and Tooling Technology in Jewelry CAD, Computer-Aided Design & Applications, Vol. 1, No. 1-4, pp. 569-575.
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