Shape Design & Styling

Generative Shape Design

Converting a Shape Design Feature into a Datum

Using the Shape Design factory to convert a Shape Design feature into a datum

Use Case

Abstract

This article discusses the CAAGsiDatum use case. This use case explains how to convert feature into datum.

What You Will Learn With This Use Case
The CAAGsiDatum Use Case

What Does CAAGsiDatum Do

How to Launch CAAGsiDatum

Where to Find the CAAGsiDatum Code

Step-by-Step

In Short

References

What You Will You Learn With This Use Case

This use case illustrate the ability to convert any Wireframe and Shape Design feature into a Datum.
Wireframe and Shape Design features to be converted do not have any child, that is to say, they do not aggregate other features (Ex: contextual features)

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The CAAGsiDatum Use Case

CAAGsiDatum is a use case of the CAAGSMInterfaces.edu framework that illustrates the ConvertToDatum method of theCATIGSMFactory interface of the GSMInterfaces framework.

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What Does CAAGsiDatum Do

The goal of CAAGsiDatum is to take the result of surface features of the CAAGsiNozzle use case, join them and convert the join into a corresponding datum feature (skin surface).

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How to Launch CAAGsiDatum

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

Launch the use case as follows:

With Windows

e:>CAAGsiDatum inputDirectory\GAAGsiNozzle.CATPart outputDirectory\CAAGsiDatum.CATPart

With UNIX

$ CAAGsiDatum inputDirectory/GAAGsiNozzle.CATPart outputDirectory/CAAGsiDatum.CATPart

where:

`outputDirectory`	The directory into which `CAAGsiDatum.CATPart is saved`
`inputDirectory`	The directory into which `CAAGsiNozzle.CATPart is found`
`CAAGsiDatum.CATPart`	The file that contains the part created with the datum surface t

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Where to Find the CAAGsiDatum Code

The CAAGsiDatum use case is made of main program located in the CAAGsiDatum.m module of the CAAGSMInterfaces.edu framework:

Windows	`InstallRootDirectory\CAAGSMInterfaces.edu\CAAGsiDatum.m\`
Unix	`InstallRootDirectory/CAAGSMInterfaces.edu/CAAGsiDatum.m/`

The input CAAGsiNozzle.CATPart is proposed in Data.d directory of CAAGSMInterfaces.edu

Windows	`InstallRootDirectory\CAAGSMInterfaces.edu\Data.d\CAAGsiNozzle.CATPart`
Unix	`InstallRootDirectory/CAAGSMInterfaces.edu/Data.d/CAAGsiNozzle.CATPart`

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

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Step-by-Step

There are four logical step in CAAGsiDatum:

Prolog
Create the join feature
Convert to datum the join feature
Save and close session

We will now comment each of those sections by looking at the code of the main method of file CAAGsiDatum.

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Prolog

CAAGsiDatum sample first creates a session and opens the input CATPart.

Note: The important feature of the following sequence of code consists in the required call to the GetPart() method of the CATPrtContainer interfaces. \

This method allow to load in session the different containers of the part (feature container, geometric container,..)

...
// creates a session
char *pSessionName = "SampleSession";
CATSession *pSession = NULL; 
rc = Create_Session(pSessionName, pSession); 
if (NULL == pSession ) {
   cout << "(CAAGsiDatum) ERROR: Create_Session" << endl;
   TestCaseError = 1 ;
}

// loads the document and initializes it
cout << "The input document " << InputName << " is opened" << endl ;
CATDocument *pDoc = NULL; 
rc =CATDocumentServices::OpenDocument(InputName, pDoc) ;

if (NULL == pDoc ) {
   cout << "(CAAGsiDatum) ERROR CATDocumentServices::OpenDocument" << endl;
   TestCaseError = 2 ;
}

// Part Container 
CATIPrtContainer *piPartContainer = NULL ; 
CATIPrtPart_var spPrtPart; 

if ( NULL != pDoc ) { 
   // queries on the document to get the root container
   CATInit *pDocAsInit = NULL; 
   pDoc->QueryInterface(IID_CATInit, (void**)&pDocAsInit) ; 
   if ( NULL != pDocAsInit ) {

    // Extracts from document a reference to its part in hPartAsRequest
   piPartContainer = 
      (CATIPrtContainer*)pDocAsInit->GetRootContainer("CATIPrtContainer");
   pDocAsInit->Release(); pDocAsInit = NULL ;

   if( NULL != piPartContainer ) {
      CATISpecObject_var spPart = piPartContainer->GetPart() ; 
      spPrtPart = spPart ;
   } 
} 
...

Finally, the wireframe and shape design factory is retrieved. .

....
// Retrieve the Generative Shape Design Interface 
CATIGSMFactory_var spGsmFact; 
if ( NULL !=piPartContainer ) { 
   CATIGSMFactory * _pFact =NULL; 
   rc = piPartContainer -> QueryInterface(IID_CATIGSMFactory ,(void**)&_pFact);
   if (SUCCEEDED(rc) ) {
     spGsmFact = _pFact;
     if (_pFact) _pFact -> Release(); _pFact = NULL; 
  }
} 
...

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Create the join feature

Using standard creation method for join (also named assemble), sweep and loft features are joined

...
// Join 
// ------------------
CATLISTV(CATISpecObject_var) aObjectParametersAssemble;
aObjectParametersAssemble.Append(spSweep1);
aObjectParametersAssemble.Append(spLoft1);
aObjectParametersAssemble.Append(spSweep2);
aObjectParametersAssemble.Append(spLoft2);

// Create feature 
double MergingDistanceTol = 0.001 ; 
CATBoolean iCheckConnexity = TRUE ; 

CATICkeParm_var spParm;
CATICkeParmFactory_var spCkeFact = spGsmFact ; 
if (!!spCkeFact) { 
   spParm = spCkeFact -> CreateLength("MergingDistance",MergingDistanceTol/1000.0);
}
CATIGSMAssemble_var spAssemble = spGsmFact -> CreateAssemble(aObjectParametersAssemble,spParm,iCheckConnexity);
aObjectParametersAssemble.RemoveAll();

// Insert in procedural view 
// ------------------
CATISpecObject_var spSpecTmp = spAssemble;
if (NULL_var != spSpecTmp) { 
   // Insert in procedural view 
   CATIGSMProceduralView_var ispProcView = spSpecTmp;
   if (NULL_var != ispProcView ) {
      rc = ispProcView ->InsertInProceduralView();
   }
}

// Update 
CAAGsiObjectUpdate(spSpecTmp);
...

The join feature is then

Insert in the procedural view thanks to the InsertInProceduralView method of CATIGSMProceduralView interface of GSMInterfaces framework
Updated thanks to generic service CAAGsiObjectUpdate [4]

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Convert to datum the join feature

Verify that the feature to convert is not already a Datum

....
// Check the feature to convert is not already a Datum 
CATIMf3DBehavior_var ispBehave(ispSpec);
if(NULL_var != ispBehave ){

  if ( FAILED( ispBehave -> IsADatum() ) ) { 
      .... 
      }
}
...

Use the ConvertToDatum method of CATIGSMFactory interface.
This method is only available for features which do not have any child (do not aggregate other features) , The argument "Verif" allow to verify it.

For multi-domain feature, one datum feature is generated by domain of the original feature

....
CATListValCATISpecObject_var *ListDatum=NULL;

// Convert Spec in one or more Datum 
int iVerif =1 ;   // Check feature do not have any child 
rc = ispGsmFact->ConvertToDatum(ispSpec, ListDatum,iVerif);
if (FAILED(rc)) return E_FAIL; 
...

Once created the datum feature got the representation of the the original feature thus it is mandatory to remove the original feature
This operation has to be done in 2 step

Dispatch the delete event to the model (in interactive session this make the visualization to be re-drawed)
Delete the feature itself in using "RemoveChild" of CATIDescendant interface if the feature is aggregated or the "Remove" of LifeCycleObject if not

....
// Delete of Procedural Specification 
// -- Model event for delete / update visualization 
CATIModelEvents_var IME(ispSpec);
if(NULL_var != IME) {
    CATDelete info(ispSpec->GetImpl());
    IME->Dispatch(info);
}

// -- Delete Specification 
CATISpecObject_var ispFather = ispSpec->GetFather();
// Specification is aggretated in the prodecural view 
if (NULL_var != ispFather) {
   ispFather->Release();
   CATIDescendants_var ispDes = ispFather;
   ispDes->RemoveChild (ispSpec);
}
// Specification is not in the prodecural view 
else {
   LifeCycleObject_var LCO = ispSpec;
   LCO -> remove();
} 
....

The Datum is created , previous feature is deleted, now the Datum has to be inserted in the procedural view as for any other shape designs feature (Wires, Surfaces and Volumes created in CATIGSMFactory).

....
// Insert in procedural view 
int i;
int size = AllDatums.Size();
for(i=1;i<=size;i++) {
   CATIGSMProceduralView_var curobj = AllDatums[i];
   if (NULL_var != curobj ) {
   rc = curobj->InsertInProceduralView();
   if (FAILED(rc)) cout << " (CAAGsiDatum)  Failed to insert datum in procedural view" << endl ;
....

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Save and close session

Save part and close the session

... 
// save  
if (NULL != OutputName )      {    
    rc = CATDocumentServices::SaveAs  (*pDoc, OutputName );
    if (SUCCEEDED(rc))   {
            cout << " (CAAGsiDatum)  Document saved " << endl;
     }
     else {
            cout << " ERROR in saving document " <<  endl ;
     }
}    
// Closes the document
CATDocumentServices::Remove(*pDoc);
   
// Ends session and drops document	
Delete_Session("SampleSession");
...

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In Short

This use case has demonstrated the way to convert de Datum from an existing feature.

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References

[1]	Building and Launching a CAA V5 Use Case
[2]	About Generative Shape Design Features
[3]	Inserting a Shape Design Feature in the procedural view
[4]	Updating a shape Design feature
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History

Version: 1 [May 2004]	Document created
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