Design of Geomagic Plug-in based RE and RP System of 3D Crafts

Transcription

1 Advanced Materials Research Online: ISSN: , Vols , pp doi: / Trans Tech Publications, Switzerland Design of Geomagic Plug-in based RE and RP System of 3D Crafts LIU Xiang-yan 1, a, WU Shi-lin 2,b 1 Wuhan University of Textile, Wuhan, Hubei,China, Wuhan University of Textile, Wuhan, Hubei,China, a whliuxy@yahoo.cn, b wslsw540@gmail.coml Keywords: Geomagic plug-in; 3D Crafts; RE; RP Abstract. This paper put forward a design of Geomagic Plug-in based RE and RP System of 3D crafts and narrates the design method of the system software after giving some introduction to the design method of Geomagic plug-in. The system is an integration of RE and RP, with which we can easily make gifts with individuation and customization. Many experiments were carried out and the results showed that the design was reasonable and feasible and the research on the system was significant. Introduction Geomagic Studio is professional reverse engineering software developed by American Raindrop Geomagic Software Company. It is commercial software and is currently most powerful in point cloud processing and 3D surface reconstruction. With Geomagic software it is easy to reconstruct a perfect polygon model mesh from the scanned point cloud data, which can be converted to NURBS surfaces automatically. And you can quickly build its STL model. Geomagic Studio also provides support for plug-in, making it possible for users to personalize the application extensions and providing facilities for future software upgrades and extensions. With its powerful surface point cloud processing and 3D surface reconstruction, geomagic plug-in based RE and RP software of 3D Crafts is able to integrate reverse design and rapid prototyping of 3D crafts. Framework of geomagic plug-in Plug-in can extend and strengthen the software without modifying program s main body. After the plug-in interface is released, any company or individual can develop their own plug-ins to solve some operational inconvenience or add new function, achieving software development of real meaning of the "plug and pull". Plug-in API provided by geinagic allows third-party software developers to create external command running in the geomagic, in order to achieve personalized function expansion of geomagic. The current version (version5.0) of geomagic plug-in platform framework primarily supports integrating data acquisition and point cloud processing into geomagic software, and its functions of later version will be further strengthened, which will allow access to more internal commands of geomagic software[1]. Plug-in-based application is composed of application framework, plug-in interface, plug-ins, and public library,and Fig.1 shows the basic framework. Application framework is responsible for the overall operation of the application, and plug-in interface is a protocol, according to which you can add plug-ins to your application. Plug-in is responsible for achieving the requirements. Usually, applications supporting plug-ins place extension plug-ins in a specified directory. When a application is executed, it first search in this directory to make sure if there is a plug-in, If there is, it inserts it into the application, and it releases the plug-in at termination of execution. Public library is a set of functions or classes, which can be called by both application framework and plug-ins. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, (ID: , Pennsylvania State University, University Park, USA-13/05/16,03:40:05)

2 298 Equipment Manufacturing Technology and Automation Application framewore plug-in interface 3D object Scanning plug-in 3D scanner Point cloud data Geomagic studio STL model plug-in 1 plug-in 2 public function library Object model STL Slicing plug-in RP software 3D printer STL slicting data Fig.1 Framework of Plug-in-based application Fig.2 System function flow In windows operating system, geomagic plug-in runs in the form of dynamic form link library (DLL). Each geomagic plug-in DLL must contain the following two functions: struct GMagicPlugInInfo *GMagicPlugInVersion(void); GMagicPlugIn *GetGMagicPlugIn(int cmdnumber); The first function returns a structure pointer with information about the geomagic plug-in DLL, through which geomagic software check the version of plug-in API required by this plug-in and the number of commands contained in the plug-in. This information structure is defined as follows: struct GMagicPlugInInfo { int versionnum; int numcmds;}; Through the second function geomagic software gets the pointer of GMagicPlugIn object, which will be stored in the geomagic software and through which geomagic software accesses its representative geomagic plug-in. Geomagic plug-ins are placed in the folder of plugin under the installation directory of geomagic studio. When geomagic software is executed, the main program will search the folder for these two functions. If they are found, they will be loaded and appropriate plug-in command will appear in the Geomagic software plug-in menu. The class of GMagicPlugIn is the plugin interface, which defines how the plug-ins and geomagic main program communicate. And when developing plug-in, the developer derives his own class from it. Communication between geomagic main program and plug-ins are mainly implemented by the following two classes: GMagicMgr and GMagicDlg. GMagicMgr mainly achieves some system operations and model data manipulation and GMagicDlg is used to create and manipulate user interface dialog. System framework RE and RP system of 3D crafts integrate rapid 3D object modeling and prototyping. Its function is to obtain 3D surface data of crafts, reconstruct their 3D data model and make their physical models. With this system, users can quickly and easily make personalized and customized gifts and souvenirs. The Function flow of RE and RP system of 3D crafts is shown in Fig.2.The software contain the following three parts: scanning plug-in, STL slicing plug-in and RP (Rapid prototyping) software. And they are developed using Visual C++ [2, 3, 4], which is an object-oriented programming language. Scanning plug-in and STL slicing plug-in are geomagic plug-ins, which can be called by geomagic main program in the form of DLL but not run separately. Scanning plug-in is responsible for controlling the scanner to acquire the point data of 3D objects and saving the point data to geomagic for following data processing [5,6,7]. Geomagic studio is responsible for point data processing, surface reconstruction and exporting the STL model of the 3D objects. STL slicing plug-in is responsible for slicing the STL model, filling the polygon of each layer with scanning line to generate track points of the printer head. RP software is a stand-alone application that can run separately. And it controls the 3D printer to complete 3D model production of 3D objects using the data obtained by STL slicing plug-in.

3 Advanced Materials Research Vols Design of System software The 3D scanner which is based on structured light stereo vision [8] program consists of a projector and two cameras as shown in Fig.3. The two cameras are installed in cross direction on the same level and they observe the 3D objects from different viewpoint. Software system controls the projector to generate parallel and vertical red stripe structured light, which is projected onto the object surface. The structured light is deformed by the object surface shape and the images of the deformed light are acquired by both two cameras. The deformation of structured light stripes depends on relative position of the two cameras, position of the projector and the surface shape of 3D objects. When positions of camera and projector are fixed, both internal and external parameters of the two cameras and their relative position is known, it is possible to obtain the 3D coordinates of a surface point form the two images of deformed stripes acquired by two cameras. Through controlling the structured light stripe to move slowly to sweep the whole surface of 3D objects it is possible to obtain the 3Dcoordinates of the object from a specified perspective [9,10]. Through projecting structured light stripe from different directions to the same object surface, point cloud data of different perspective can be obtained. And the point cloud of multi-views can be spliced to integrate the point cloud data of whole object surface. reading STL model data compute the Intersection of the triangle and the cross-section filling the polygon using scanning lines sorting contour points Fig3.Framework of 3D scanner track points of the printer head Fig.4 Flow chart of STL slicing Scanning plug-in controls the 3D scanner to acquire point cloud of 3D objects, and saves the data into geomagic main program [11, 12]. Such commands relative to 3D measurement as parameter setting, structured light control, scanner calibration, saving of calibration files, and reading of calibration files are all implemented in the plug-in. After scanning, scanned point cloud data can be imported directly to geomagic studio which is powerful reverse engineering software. With its powerful function it is easy to implement pre-processing of point cloud data, multi-cloud model stitching and the reconstruction task, and to obtain the STL model of the 3D object. STL slicing plug-in is responsible for slicing the STL model, filling the polygon of each layer with scanning line to generate track points of the printer head. STL model file represents entity with a series of triangles [13], each of which is represented by a unit surface normal indicating its direction and three coordinates indicating positions of triangle vertices. Flow chart of STL slicing is shown as Fig.4. Algorithm of active-edge-table filling, such data structures as CArray which is dynamic array, lists and so on are all used in the scanning line filling program of polygon and this improved the speed of slicing and scanning line filling of polygons. RP software runs on PC and controls the 3D printer to complete 3D model production of 3D objects using the data obtained by STL slicing plug-in. PC communicate with 3D printer through serial port. There are many ways of programming for serial port and the most commonly used way is programming using the control of MSComm which is developed by Microsoft for communication of serial ports. This control is developed using advanced programming language and it is a bridge between serial communication program and PC serial port, which makes it easier to develop serial communication program. In the development of RP software which is specific for RE and RP system of 3D crafts, MSComm is used in programming of serial port communication. The serial port can work as required after being set its attributes and being added event response codes. Most attributes of MSComm are readable and writable. S For more specific using method of this control, you can refer to MSDN.

4 300 Equipment Manufacturing Technology and Automation Experiments Fig.5 Point cloud Fig.6 Reconstructed model Basing on the framework of 3D scanner and the method of 3D data acquisition proposed in this paper and using scanning plug-in designed in this paper many experiments were implemented and received satisfactory results. Point cloud data scanned using 3D scanner is shown in Fig.5 and 3D model obtained in geomagic studio is shown in Fig.6. For Prototype of 3D Printer is not developed for experiments, in order to verify track points of the 3D printer head generated by STL slicing plug-in and debug RP software, two PC are used. One serves as host computer and the other simulates 3D Printer. Model of 3D printer is built to simulate production of 3D model, and the results are ideal to some extent. Conclusions This paper presented a design plan of a geomagic plug-in based RE and RP system of 3D crafts and described the design methods and ideas of the software supporting this system. Using this system, a large number of experiments are implemented and the results showed that the design plan is reasonable and feasible. References [1] Geomagic Plugin Technical Reference for use with Geomagic Qualify and Studio. September 14, 2004 [2] GuangjunZhang. "machine vision". Science press. Beijing In Chinese [3] ZeshengTang etc. Computer graphics. Tsinghua university press, 2000 In Chinese [4] ZhangJun Sally ShuzhiLiu. "Visual c + + practice and improve - serial communication article" and engineering application. China railway press. Beijing. : January 2006 [5] Will P.M., Pennington K.S.,Norel technique for image processing [J]. Proc.IEEE, 1972, 60(6):669~680 [6] Popplestone R.J., Ambler A.P. Forming models of plane and cylinder faceted bullies from light stripes[c].in:proc.4thintern, Joint Conf.Artif.Intell. 1975: 664~668 [7] Agin G.J. Binford T.O. Computer description of curved objects[c].in:proc.3 Intern Conf. Artif. Intell,Stanford, CA, 1973:629~640 [8] Potmesil M.,Generating models of solid objects by matching 3D surface segments [J].In:Proc 8thIntern Joint Conf Artif Intell, Karlsruhe,1983:1089~1093 [9] Sato Y.,Kitagawa H.,Fujita H.Shape Measurement of Curved Objects Using Multiple Slit Ray Projections [J].IEEE Trans Patt Anal Mach Intell, 1982:641~646 [10] Tio J.B.K., McPherson C.A., Hall E. L.,Curved Surface Measurement for Robot Vision[C]. Proc RPIP, 1983:52~96 [11] Tsai R.Y.,A versatile camera calibration technique for high accuracy 3D machine vision metrology using of the shelf TV cameras and lenses [J]. IEEE J Robotics Autom,1987, RA-3(4):323~344 [12] Mansbach P.,Calibration of a camera and light source by fitting to a physical model [J].Computer Vis Graph Image Process, 1986, 35:200~219 [13] Kim Y C,etal. Positioning Three-dimensional objects using stereo images [J].IEEE Journal of robotics and Automation, 1987, 3(4):361~373

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