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1、 SSOLFDWLRQ UDPHZRUN What is OCAF Purpose of OCAF 1 Overview of the Architecture 2 Getting Started 3 Benefits of OCAF 4 A Look Inside OCAF The Design of OCAF 5 The Data Framework 8 Persistent Data Storage 11 Version 6 3 September 2008 Tour Opus 12 77 Esplanade du G n ral de Gaulle 92914 PARIS LA DEF
2、ENSE FRANCE Copyright 2008 by Open CASCADE S A S PROPRIETARY RIGHTS NOTICE All rights reserved No part of this material may be reproduced or transmitted in any form or by any means electronic mechanical or otherwise including photocopying and recording or in connection with any information storage o
3、r retrieval system without the permission in writing from Open CASCADE S A S The information in this document is subject to change without notice and should not be construed as a commitment by Open CASCADE S A S Open CASCADE S A S assures no responsibility for any errors that may appear in this docu
4、ment The software described in this document is furnished under a license and may be used or copied only in accordance with the terms of such a license CAS CADE and Open CASCADE are registered trademarks of Open CASCADE S A S Other brand or product names are trademarks or registered trademarks of th
5、eir respective holders NOTICE FOR USERS This User Guide is a general instruction for Open CASCADE study It may be incomplete and even contain occasional mistakes particularly in examples samples etc Open CASCADE S A S bears no responsibility for such mistakes If you find any mistakes or imperfection
6、s in this document or if you have suggestions for improving this document please contact us and contribute your share to the development of Open CASCADE Technology bugmaster Open CASCADE S A 1 What is OCAF Purpose of OCAF The Open CASCADE Application Framework OCAF is an easy to use platform for rap
7、idly developing sophisticated domain specific design applications A typical application developed using OCAF deals with two or three dimensional 2D or 3D geometric modeling in trade specific Computer Aided Design CAD systems manufacturing or analysis applications simulation applications or illustrat
8、ion tools Developing a design application requires addressing many technical aspects In particular given the functional specification of your application you must at least Design the architecture of the application definition of the software components and the way they cooperate Define the data mode
9、l able to support the functionality required a design application operates on data maintained during the whole end user working session Structure the software in order to synchronize the display with the data commands modifying objects must update the views support generalized undo redo commands thi
10、s feature has to be taken into account very early in the design process Implement the function for saving the data if the application has a long life cycle the compatibility of data between versions of the application has to be addressed Build the application user interface By providing architectura
11、l guidance and ready to use solutions to these issues OCAF helps you to develop your application significantly faster you concentrate on the application s functionality What is OCAF Open CASCADE S A 2 Overview of the Architecture OCAF provides you with an object oriented Application Document Attribu
12、te model This consists of C class libraries The main class Application is an abstract class in charge of handling documents during the working session Services provided by this class include Creating new documents Saving documents and opening them Initializing document views The document implemented
13、 by the concrete class Document is the container for the application data Its main purpose is to centralize notifications of data editing in order to provide Undo Redo Each document is saved in a single flat ASCII file defined by its format and extension a ready to use format is provided with OCAF A
14、pplication data are attributes that is instances of classes derived from the Attribute abstract class organized according to the OCAF Data Framework The OCAF Data Framework references aggregations of attributes using persistent identifiers in a single hierarchy the Data Framework is described in the
15、 next chapter A Look Inside OCAF A wide range of attributes come with OCAF including Primitive attributes such as Integer Real Name and Comment Shape attribute containing the geometry of the whole model or elements of it Other geometric attributes such as Datums points axis and plane and Constraints
16、 such as tangent to at a given distance from a given angle concentric etc Modeling step and Function attributes the purpose of these attributes is to rebuild objects after they have been modified parameterization of models Visualization attributes these attributes allow data to be visualized in a 2D or 3D viewer User attributes that is attributes typed by the application In addition application specific data can be added by defining new attribute classes naturally this changes the standard file
