Geometric Modeler

What You Will Learn With This Use Case

The use case explains how to create implicit objects and illustrates how their life cycle is managed.

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About Implicit Objects

Implicit objects are created by the implicit factory. They are automatically removed when all the objects that point to them are removed with the RemoveDependancies option of the CATICGMContainer::Remove method.

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The CAAGobLifeCycleImplicit Use Case

CAAGobLifeCycleImplicit is a use case of the CAAGeometricObjects.edu framework that illustrates GeometricObjects framework capabilities.

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What Does CAAGobLifeCycleImplicit Do

With this use case, you create an implicit CATPlane on which an implicit CATPline is created. Then this CATPLine is cloned. Because the CATCloneManager is created with the CatCGMFullDuplicate  option, a duplicate plane is created.

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How to Launch CAAGobLifeCycleImplicit

To launch CAAGobLifeCycleImplicit, you will need to set up the build time environment, then compile CAAGobLifeCycleImplicit.m along with its prerequisites, set up the run time environment, and then execute the use case [1].

If you simply type CAAGobLifeCycleImplicit with no argument, the use case executes, but doesn't save the result in an NCGM file. If you want to save this result, provide the full pathname of the NCGM file to create. For example:

With Windows CAAGobLifeCycleImplicit e:\ObjCreation.NCGM

With UNIX CAAGobLifeCycleImplicit /u/ObjCreation.NCGM

This NCGM file can be displayed using the CAAGemBrowser use case.

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Where to Find the CAAGobLifeCycleImplicit Code

The CAAGobLifeCycleImplicit use case is made of a main named CAAGobLifeCycleImplicit.cpp located in the CAAGobLifeCycleImplicit.m module of the CAAGeometricObjects.edu framework:

where InstallRootDirectory is the directory where the CAA CD-ROM is installed.

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Step-by-Step

The main program is divided into the following steps:

1. Creating the Standard Geometry Factory
2. Creating the Implicit Geometry Factory
3. Creating the Implicit Objects: the CATPlane, the Initial CATPline and the Cloned CATPLine
4. Removing the two Plines with RemoveDependancies and Attempting to create a New CATPline
5. Writing the Model and Closing the Container

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Creating the Standard Geometry Factory

The geometry factory (CATGeoFactory) creates and manages all the CATICGMObject  This creation is done by the global function ::CATCreateCGMContainer. Notice that the factory can be defined by reading a NCGM file that was previously stored. In that case, the global function ::CATLoadCGMContainer must be used.

CATGeoFactory* piGeomFactory = ::CATCreateCGMContainer() ;
if (NULL == piGeomFactory) return (1);

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Creating the Implicit Geometry Factory

The implicit factory is retrieved from the standard factory by using the CATGeoFactory::GetImplicitGeoFactory( ) method.

CATGeoFactory * piImplicitFactory =piGeomFactory->GetImplicitGeoFactory( );
if (NULL == piImplicitFactory) return (1); 

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Creating the Implicit Objects: the CATPlane, the Initial CATPline and the Cloned CATPLine

You create implicit objects exactly like you would create standard or explicit objects, except that the implicit factory is to be used.

There are two ways to create a cloned objects:

• either in full duplication mode, in this case the objects referred to by the object to be cloned are duplicated  by the CATCloneManager (the CATPline underlying plane is duplicated).
• or in single duplication mode, in this case only the object to be cloned is duplicated.

CATPlane * piPlane = piImplicitFactory->CreatePlane(CATMathOIJ);
...
CATPLine * pPline =  piImplicitFactory->CreatePLine   (p1, p2, piPlane );
// ----- Clone pPline - Full duplication mode
//       A duplicate plane is created because the CatCGMFullDuplicate
//       is specified - if the default option is used, the duplicated 
//       PLine points to the already existing plane.
CATCloneManager * pCloneManager= new CATCloneManager(piImplicitFactory, CatCGMFullDuplicate); 
...
pCloneManager->Add(pPline);
pCloneManager->Run();
CATICGMObject* piClonedPLine=NULL;
piClonedPLine = pCloneManager->ReadImage(pPline);

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Removing the Two Plines with RemoveDependancies and Attempting to Create a New CATPline

The RemoveDependancies option only applies to implicit objects. By using it, you will remove all the implicit objects no longer used by the object which is to be removed.

Case 1

CATCloneManager in full duplication option
If you remove pPline with the RemoveDependancies options, piPlane being an implicit object, it is removed. Any attempt to re-use  it to create another Pline will result in a throw. Removing the cloned CATPLine will not change anything.

Case 2

CATCloneManager is single duplication option
if you remove pPline with RemoveDependancies but not piClonedPLine, piPlane will not be removed because it is still pointed to by piClonedPLine and you will be able to re-use it to create a new PLine.
but, if you remove pPline as well as piClonedPLine with the RemoveDependancies option,  piPlane will be removed because it is no longer pointed to by other objects and you will not be able to re-use piPlane.

piImplicitFactory->Remove(pPline,CATICGMContainer::RemoveDependancies);
piImplicitFactory->Remove(piClonedPLine,CATICGMContainer::RemoveDependancies);

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Writing the Model and Closing the Container

To save the model in a file, the ::CATSaveCGMContainer global function is used. Notice that in the use case, the save is conditioned by an input parameter representing the file inside which the model must be saved.

The use case ends with the closure of the geometry factory, done by the ::CATCloseCGMContainer global function.

 if(1==toStore)
 {
#ifdef _WINDOWS_SOURCE
   ofstream filetowrite(pfileName, ios::binary ) ;
#else
   ofstream filetowrite(pfileName,ios::out,filebuf::openprot) ;
#endif

   ::CATSaveCGMContainer(piGeomFactory,filetowrite);
   filetowrite.close();
 }	

 //
 // Closes the container
 //	
 ::CATCloseCGMContainer(piGeomFactory);

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In Short

This use case describes how to create implicit objects and illustrates how the RemoveDependancies option affects their life cycle.

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References

History

Copyright © 2003, Dassault Systèmes. All rights reserved.