AutoCAD DevBlog

Modifying an Associative Path Array using API

By Balaji Ramamoorthy

In this blog post, we will look at modifying an associative path array. A path array can either be using the item spacing or the item count depending on how the path array is configured in its properties. The below code snippet decrements the item count or increases the item spacing to reduce the number of items along the path.

Here is a recording and a code snippet :

 #include  "AcDbAssocManager.h" 

 #include  "AcDbAssocArrayActionBody.h" 

 #include  "AcDbAssocArrayPathParameters.h" 

 Acad::ErrorStatus es;

 ads_name ename; 

 ads_point pickPt;

 int  rc = acedEntSel(_T("\\nSelect Entity" ), ename, pickPt);

 if  (rc != RTNORM)

 	return ;

 AcDbObjectId entId; 

 acdbGetObjectId(entId, ename);

 AcDbObjectPointer <AcDbEntity> pEntity(entId, AcDb::kForRead);

 if ((es = pEntity.openStatus()) != Acad::eOk)

 	return ;

 if (! AcDbAssocArrayActionBody::isAssociativeArray(pEntity))

 {

 	acutPrintf(ACRX_T("\\nNot an associative array !" ));

 	return ;

 }

 AcDbObjectId actionBodyId 

 	= AcDbAssocArrayActionBody::getControllingActionBody(

 	pEntity, NULL);

 pEntity->close();

 AcDbAssocArrayActionBody* pArrayActionBody = NULL;

 if ( (es = acdbOpenAcDbObject(

 	(AcDbObject*&)pArrayActionBody, 

 	actionBodyId, 

 	AcDb::kForWrite)) != Acad::eOk)

 	return ;

 AcDbAssocArrayParameters *pAssocArrayParams 

 	= pArrayActionBody->parameters();

 AcDbAssocArrayPathParameters *pAssocArrayPathParams 

 	= AcDbAssocArrayPathParameters::cast(pAssocArrayParams);

 AcDbAssocArrayPathParameters::Method pathArrMethod 

 	= pAssocArrayPathParams->method();

 if (pathArrMethod 

 	== AcDbAssocArrayPathParameters::Method::kDivide)

 {

 	//The Divide method arranges the given number of items on the  

 	// entire path equidistantly.  

 	// So we will decrement the number of items along the path 

 	pAssocArrayPathParams->setItemCount

 		(pAssocArrayPathParams->itemCount() - 1);

 }

 else  if (pathArrMethod 

 	== AcDbAssocArrayPathParameters::Method::kMeasure)

 {

 	double  itemSpacingBefore 

 		= pAssocArrayPathParams->itemSpacing();

 	//The Measure method arranges the given number of items  

 	// using the specified item spacing along the path. 

 	pAssocArrayPathParams->setItemSpacing

 		(pAssocArrayPathParams->itemSpacing() * 1.1);

 	double  itemSpacingAfter 

 		= pAssocArrayPathParams->itemSpacing();

 	if (fabs(itemSpacingBefore-itemSpacingAfter) < 0.0001)

 	{// Reduce the number of items 

 		pAssocArrayPathParams->setItemCount

 			(pAssocArrayPathParams->itemCount() - 1);

 		pAssocArrayPathParams->setItemSpacing

 			(pAssocArrayPathParams->itemSpacing() * 1.1);

 	}

 }

 pArrayActionBody->close();

 AcDbAssocManager::evaluateTopLevelNetwork(entId.database());

 acedUpdateDisplay();

Selected point on solid during entity selection

By Balaji Ramamoorthy

The acedEntSel method provides a way for the user to select an entity and it also provides the point that was used during the entity selection. When used on a 2D entity, the point returned by acedEntSel is quite useful if you need that information to further work on the entity and perform tasks such as break, trim etc. 

However, when acedEntSel is used to select a solid, the point returned is in the UCS XY Plane regardless of where on the solid you pick. if you use an OSNAP while selecting the solid entity, the point will be on the solid. If the point on the solid that was used while selecting the solid is important for doing further processing in your code, here is a way to get that.

In the following code, a ray is created along the viewing direction with which we will find the intersection points of the solid. The code displays all the intersection points as though the ray pierced the solid. But the first intersection point should provide the selection point, in case you are only interested in that.

Please note that, in AutoCAD 2015 and AutoCAD 2016, the "AcBrBrep::getLineContainment" returns lesser number of hits during an intersection test. This behavior has been logged with our engineering team. AutoCAD 2014 and previous releases provide the right number of hits.

Here is a recording which demonstrates the entity selection and the sample code :

 Acad::ErrorStatus es;

 // pt is in UCS coordinates and in the UCS XY plane  

 // unless a osnap is used while selecting the entity 

 // In that case, the point will be have all  

 // the three coordinate values in UCS. 

 ads_name  ename;

 ads_point pt;

 int  ret = acedEntSel(_T("\\nPick a solid : " ), ename, pt);

 if  (ret != RTNORM)

 	return ;

 AcDbObjectId entId = AcDbObjectId::kNull;

 es = acdbGetObjectId(entId, ename);

 AcDbEntity *pEnt = NULL;

 AcDb3dSolid *pSolid = NULL;

 es = acdbOpenAcDbEntity(pEnt, entId, AcDb::kForRead);

 pSolid = AcDb3dSolid::cast(pEnt);

 if (pSolid == NULL)

 {

 	acutPrintf(L"\\nSelected entity was not a solid.\\n" );

 	return ;

 }

 // Get the WCS coordinates of the selected point 

 AcGePoint3d wcsPt = AcGePoint3d::kOrigin;

 acdbUcs2Wcs(pt, pt, 0);

 wcsPt = asPnt3d(pt);

 resbuf viewRb;

 AcGePoint3d  target = AcGePoint3d::kOrigin; 

 // TARGET is in UCS 

 acedGetVar(_T("TARGET" ), &viewRb); 

 target = asPnt3d(viewRb.resval.rpoint);

 acdbUcs2Wcs(asDblArray(target), asDblArray(target), 0);

 AcGeVector3d dir = AcGeVector3d::kIdentity; 

 // VIEWDIR is in UCS 

 acedGetVar( ACRX_T("VIEWDIR" ), &viewRb ); 

 dir = asVec3d(viewRb.resval.rpoint);

 acdbUcs2Wcs(asDblArray(dir), asDblArray(dir), 1);

 AcGePoint3d  position = target + dir;

 dir = dir.normalize().negate();

 AcGeLine3d testRay(

 	wcsPt.project(AcGePlane(position, dir), dir.negate()),

 	dir);

 AcBrBrep*pBrep = new  AcBrBrep();

 pBrep->setSubentPath( AcDbFullSubentPath

 	( pEnt->objectId(),  AcDbSubentId()));

 AcBr::ErrorStatus bres;

 AcBrHit *pHits = NULL;

 Adesk::UInt32 nHitsFound = 0;

 // Find all hits 

 bres = pBrep->getLineContainment(

 	testRay, 0, nHitsFound, pHits );

 if (bres == AcBr::eOk)

 {

 	for ( Adesk::UInt32 i = 0; i < nHitsFound; i++) 

 	{

 		AcBrEntity *pHitEntity = NULL;

 		pHits[i].getEntityHit( pHitEntity );

 		if ( pHitEntity == NULL )

 			continue ;

 		if ( ! pHitEntity->isKindOf(AcBrBrep::desc()))

 		{

 			AcGePoint3d hitPt;

 			pHits[i].getPoint(hitPt);

 			AcDbPoint *pDbPt = new  AcDbPoint(hitPt);

 			PostToDb(pDbPt);

 			es = pDbPt->close();

 		} 

 		delete  pHitEntity;

 	}

 	delete  [] pHits;

 }

 delete  pBrep;

 pEnt->close();

Identifying layer property overrides for a viewport

By Balaji Ramamoorthy

Here is a sample code to identify the layers that have their properties overridden for a viewport and to list the property overrides. The "AcDbLayerTableRecord::hasAnyOverrides" should quickly let us know if there are any overrides for any of the viewports. If it does exist, we can get to the details using "AcDbLayerTableRecord::hasOverrides" and provide the ObjectId of the viewport for which we want to know the overrides.

 Acad::ErrorStatus es;

 AcDbDatabase *pDb 

 	= acdbHostApplicationServices()->workingDatabase();

 ads_point pt;

 ads_name ename;

 if  ( RTNORM != 

 	acedEntSel(ACRX_T("Select a viewport :" ), 

 	ename, pt))

 	return ;

 AcDbObjectId vpid = AcDbObjectId::kNull;

 if  ( Acad::eOk != acdbGetObjectId(vpid, ename ))

 	return ;

 AcDbObjectId layerId = AcDbObjectId::kNull;

 AcDbLayerTable* pLayerTable;

 pDb->getSymbolTable(pLayerTable, AcDb::kForRead);

 AcDbLayerTableIterator *pIter = NULL;

 AcDbLayerTableRecord *pLTR = NULL;

 pLayerTable->newIterator(pIter);

 for  (;! pIter->done(); pIter->step()) 

 {

 	es = pIter->getRecord(pLTR, AcDb::kForRead);

 	if (! pLTR->hasAnyOverrides())

 	{

 		pLTR->close();

 		continue ;

 	}

 	if (! pLTR->hasOverrides(vpid))

 	{

 		pLTR->close();

 		continue ;

 	}

 	TCHAR *lname;

 	pLTR->getName(lname);

 	acutPrintf(L"\\n Layer : %s has the following overrides :" ,

 		lname);

 	bool  isOverriddenForVP = Adesk::kFalse;

 	AcCmColor clr = pLTR->color(vpid, isOverriddenForVP);

 	if (isOverriddenForVP)

 	{

 		acutPrintf(L"\\n Color override" );

 	}

 	isOverriddenForVP = Adesk::kFalse;

 	AcDbObjectId ltypeId 

 		= pLTR->linetypeObjectId(

 		vpid, isOverriddenForVP);

 	if (isOverriddenForVP)

 	{

 		acutPrintf(L"\\n Linetype override" );

 	}

 	isOverriddenForVP = Adesk::kFalse;

 	AcDb::LineWeight lw 

 		= pLTR->lineWeight

 		(vpid, isOverriddenForVP);

 	if (isOverriddenForVP)

 	{

 		acutPrintf(L"\\n Lineweight override" );

 	}

 	isOverriddenForVP = Adesk::kFalse;

 	ACHAR *psName = pLTR->plotStyleName

 		(vpid, isOverriddenForVP);

 	if (isOverriddenForVP)

 	{

 		acutPrintf(L"\\n Plotstyle override" );

 	}

 	pLTR->close();

 }

 delete  pIter;

 pLayerTable->close();

Extracting pattern, text and shapes used in linetypes

By Balaji Ramamoorthy

As you may already know, linetype definition in AutoCAD consists of series of values representing the pattern and can include text and shapes. Here is a sample code to iterate the linetypes loaded in the database and display the definition. In case of embedded shapes, a preview of the shape is created by adding an AcDbShape to the modelspace.

 Acad::ErrorStatus es;

 double  previewOffset = 5.0;

 AcGePoint3d pos = AcGePoint3d::kOrigin;

 AcApDocument *pActiveDoc 

 	= acDocManager->mdiActiveDocument();

 AcDbDatabase *pDB = pActiveDoc->database();

 AcDbLinetypeTable* pLineTypeTable = NULL; 

 if  ( pDB->getLinetypeTable(

 	pLineTypeTable, AcDb::kForRead) != Acad::eOk) 

 	return ;

 es = acDocManager->lockDocument(pActiveDoc);

 AcDbBlockTableRecordPointer 

 	pMS(ACDB_MODEL_SPACE, pDB, AcDb::kForWrite);

 AcDbLinetypeTableIterator* pIter = NULL; 

 es = pLineTypeTable->newIterator( pIter); 

 es = pLineTypeTable->close(); 

 for (;! pIter->done(); pIter->step()) 

 { 

 	AcDbLinetypeTableRecord* pLinetype = NULL; 

 	if  ( pIter->getRecord( pLinetype, 

 		AcDb::kForRead) == Acad::eOk) 

 	{ 

 		const  ACHAR *pLinetypeName = NULL; 

 		es = pLinetype->getName(pLinetypeName); 

 		acutPrintf(_T("\\nLinetype : %s" ), 

 			pLinetypeName); 

 		for ( int  dash = 0; dash < 

 			pLinetype->numDashes(); ++dash) 

 		{ 

 			int  shapeNumber 

 				= pLinetype->shapeNumberAt(dash);

 			double  dashLen 

 				= pLinetype->dashLengthAt(dash); 

 			AcDbObjectId objIdShape

 				(pLinetype->shapeStyleAt( dash)); 

 			if  ( objIdShape == AcDbObjectId::kNull) 

 			{ 

 				const  ACHAR *pText = NULL; 

 				es = pLinetype->textAt(dash, pText);

 				if (pText == NULL)

 					acutPrintf(_T("\\nDash : %d DashLen : %lf" ),

 					dash,  dashLen); 

 				else

 					acutPrintf(_T("\\nDash : %d Text : %s" ), 

 					dash,  pText); 

 				continue ;

 			}

 			// Shape involved, lets preview it...

 			AcDbObject* pObject = NULL;

 			es = acdbOpenAcDbObject(

 				pObject, objIdShape, AcDb::kForRead);

 			AcDbTextStyleTableRecord* pTextSyleTableRec 

 				= AcDbTextStyleTableRecord::cast( pObject); 

 			Adesk::Boolean isShapeFile 

 				= pTextSyleTableRec->isShapeFile();

 			if (isShapeFile)

 			{

 				// Create a preview of the shape

 				AcDbShape *pShape = new  AcDbShape

 					(AcGePoint3d::kOrigin, 1.0); 

 				if ( pShape->setShapeNumber(shapeNumber) 

 					!= Acad::eOk || 

 					pShape->setStyleId(objIdShape) 

 					!= Acad::eOk)

 				{

 					delete  pShape;

 					pShape = NULL;

 				}

 				if (pShape)

 				{

 					es = pShape->setWidthFactor(1.0);

 					AcDbObjectId id;

 					es = pMS->appendAcDbEntity(id, pShape);

 					es = pShape->setPosition(pos);

 					pos += 

 					AcGeVector3d::kXAxis * previewOffset;

 					es = pShape->setSize(1);

 					es = pShape->setRotation(0);

 					es=pShape->close();

 					const  ACHAR *pShapeFileName = NULL; 

 					Acad::ErrorStatus es 

 						= pTextSyleTableRec->fileName

 						(pShapeFileName); 

 					acutPrintf(_T("\\nDash : %d 

 							ShapeNumber : %d 

 							ShapeName : %s 

 							ShapeFile : %s"), 

 							dash, shapeNumber, 

 							pShape->name(), pShapeFileName);

 				}

 			}

 			else

 			{

 				const  ACHAR *pText = NULL; 

 				es = pLinetype->textAt(dash, pText);

 				acutPrintf(_T("\\nDash : %d Text : %s" ), 

 					dash,  pText); 

 			}

 			pObject->close(); 

 		}

 		pLinetype->close();

 	}

 }

 delete  pIter;

 es = acDocManager->unlockDocument(pActiveDoc);

The output generated by this code snippet is as seen in this screenshot :

Programmatically mimic the Burst command

By Balaji Ramamoorthy

The "Burst" command from the express tools is quite useful when exploding block references with attributes. Unlike the usual explode command, it leaves the attributes unchanged when a block reference is exploded.

Here is a sample code to mimic the Burst command using the AutoCAD .Net API. It first explodes a block reference and replaces any attribute definitions in the exploded entity collection by a DBText.

 [CommandMethod("EB" , CommandFlags.UsePickSet)]

 public  void  ExplodeBock()

 {

     Document doc 

         = Application.DocumentManager.MdiActiveDocument;

     Editor ed = doc.Editor;

     PromptSelectionResult psr = ed.SelectImplied();

     if  (psr.Status != PromptStatus.OK)

     {

         ed.WriteMessage(@"Please select the  

         block references to explode and  

         then run the command" );

         return ;

     }

     using  (SelectionSet ss = psr.Value)

     {

         if  (ss.Count <= 0)

         {

             ed.WriteMessage(@"Please select the  

             block references to explode and  

             then run the command" );

             return ;

         }

         Database db = doc.Database;

         using  (Transaction tr 

             = db.TransactionManager.StartTransaction())

         {

             ObjectId msId 

             = SymbolUtilityServices.GetBlockModelSpaceId(db);

             BlockTableRecord ms = tr.GetObject(msId, 

                 OpenMode.ForWrite) as  BlockTableRecord;

             foreach  (SelectedObject selectedEnt in  ss)

             {

                 BlockReference blockRef = tr.GetObject(

                 selectedEnt.ObjectId, 

                 OpenMode.ForRead) as  BlockReference;

                 if  (blockRef != null )

                 {

                     DBObjectCollection toAddColl 

                             = new  DBObjectCollection();

                     BlockTableRecord blockDef 

                     = tr.GetObject(

                     blockRef.BlockTableRecord,

                     OpenMode.ForRead) as  BlockTableRecord;

                     // Create a text for const and  

                     // visible attributes 

                     foreach  (ObjectId entId in  blockDef)

                     {

                         if  (entId.ObjectClass.Name 

                             == "AcDbAttributeDefinition" )

                         {

                             AttributeDefinition attDef 

                             = tr.GetObject(entId, 

                             OpenMode.ForRead) 

                             as  AttributeDefinition;

                             if  ((attDef.Constant && 

                                 !attDef.Invisible))

                             {

                                 DBText text = new  DBText();

                                 text.Height = attDef.Height;

                                 text.TextString 

                                     = attDef.TextString;

                                 text.Position = 

                                 attDef.Position.TransformBy

                                 (blockRef.BlockTransform);

                                 toAddColl.Add(text);

                             }

                         }

                     }

                     // Create a text for non-const  

                     // and visible attributes 

                     foreach  (ObjectId attRefId 

                         in  blockRef.AttributeCollection)

                     {

                         AttributeReference attRef 

                         = tr.GetObject(attRefId, 

                         OpenMode.ForRead)

                         as  AttributeReference;

                         if  (attRef.Invisible == false )

                         {

                             DBText text = new  DBText();

                             text.Height = attRef.Height;

                             text.TextString 

                                 = attRef.TextString;

                             text.Position = attRef.Position;

                             toAddColl.Add(text);

                         }

                     }

                     // Get the entities from the  

                     // block reference 

                     // Attribute definitions have  

                     // been taken care of.. 

                     // So ignore them 

                     DBObjectCollection entityColl 

                     = new  DBObjectCollection();

                     blockRef.Explode(entityColl);

                     foreach  (Entity ent in  entityColl)

                     {

                         if  (! (ent is  AttributeDefinition))

                         {

                             toAddColl.Add(ent);

                         }

                     }

                     // Add the entities to modelspace 

                     foreach  (Entity ent in  toAddColl)

                     {

                         ms.AppendEntity(ent);

                         tr.AddNewlyCreatedDBObject

                         (ent, true );

                     }

                     // Erase the block reference 

                     blockRef.UpgradeOpen();

                     blockRef.Erase();

                 }

                 tr.Commit();

             }

         }

     }

 }

Reloading linetype from file

By Virupaksha Aithal

The "AcDbDatabase::loadLineTypeFile" can load linetypes from a linetype file. If the linetype with the same name already exists in the database, then the loadLineTypeFile method can return an error code. A way to force the reloading of linetype is to load the linetype in another database and clone the linetype back to the host database to replace it. Here is a code snippet to do that :

 Acad::ErrorStatus es;

 AcDbDatabase *pDb = 

     acdbHostApplicationServices()->workingDatabase();

 TCHAR szLtFile[MAX_PATH];

 if  ( RTNORM != 

     acedFindFile(_T("TrimCADLinetypes.LIN"), szLtFile) ) 

 {

 	acutPrintf(ACRX_T("\\nLinetype file not  found !"));

 	return ;

 }

 AcDbLinetypeTable *pLtTable = NULL;

 es = pDb->getLinetypeTable(pLtTable,AcDb::kForRead);

 ACHAR *szLtype = ACRX_T("FLATDOTS");

 bool isLinetypeLoaded = pLtTable->has(szLtype);

 es = pLtTable->close();

 if (isLinetypeLoaded)

 {

 	// Already loaded, try  reloading the linetype

 	AcDbDatabase *pTempDatabase 

                     = new  AcDbDatabase(true, false );

 	es = pTempDatabase->loadLineTypeFile

                                  (szLtype, szLtFile);

 	if (Acad::eOk == es)

 	{

 		AcDbLinetypeTable *pTempLtTable;

 		AcDbLinetypeTableRecord *pTempLtRec=NULL;

 		es = pTempDatabase->getLinetypeTable(

 		                pTempLtTable,AcDb::kForRead);

 		AcDbObjectId ltRecId = AcDbObjectId::kNull;

 		es = pTempLtTable->getAt(szLtype, ltRecId);

 		pTempLtTable->close();

 		AcDbObjectIdArray objIdArray;

 		objIdArray.append(ltRecId);

 		AcDbIdMapping idMap;

 		es = pDb->wblockCloneObjects(

 		            objIdArray, 

 		            pDb->linetypeTableId(), 

                     idMap, 

                     AcDb::kDrcReplace);

 		if (Acad::eOk == es)

 		{

 			acutPrintf(

 			    ACRX_T("\\nLinetype reloaded !"));

 		}

 		else 

 		{

 			acutPrintf(

             ACRX_T("\\nSorry, could not  reload Linetype !"));

 		}

 	}

 	else 

 	{

 		acutPrintf(

         ACRX_T("\\nError loading linetype from  file !"));

 	}

 	delete pTempDatabase;

 }

 else  

 {// Not  loaded, try  loading the linetype

 	if  ( Acad::eOk == 

 	    pDb->loadLineTypeFile(szLtype, szLtFile)) 

 	{

 		acutPrintf(

 		    ACRX_T("\\nLinetype loaded from  file !"));

 	}

 	else 

 	{

 		acutPrintf(

 		    ACRX_T("\\nError loading linetype from  file !"));

 	}

 }

Creating a splined leader using a Jig

By Balaji Ramamoorthy

Here is a sample code to create a splined leader using an EntityJig. This is a modified version of the sample code from this post in Kean's blog.

public class SplinedLeaderJig : EntityJig

{

    Point3dCollection _mPts;

    Point3d _mTempPoint;

    public static bool _mIsJigStarted;

 

    public SplinedLeaderJig()

        : base(new Leader())

    {

        _mPts = new Point3dCollection();

 

        Leader leader = Entity as Leader;

        leader.SetDatabaseDefaults();

 

        _mIsJigStarted = false;

 

        leader.IsSplined = true;

    }

 

    protected override SamplerStatus Sampler(JigPrompts prompts)

    {

        Editor ed

       = Application.DocumentManager.MdiActiveDocument.Editor;

 

        JigPromptPointOptions opts = new JigPromptPointOptions();

 

        opts.UserInputControls = (

            UserInputControls.Accept3dCoordinates |

            UserInputControls.NoNegativeResponseAccepted |

            UserInputControls.NullResponseAccepted);

 

        if (_mPts.Count >= 1)

        {

            opts.BasePoint = _mPts[_mPts.Count - 1];

            opts.UseBasePoint = true;

        }

 

        opts.Message = "\nSpecify leader vertex: ";

 

        PromptPointResult res = prompts.AcquirePoint(opts);

        if (_mTempPoint == res.Value)

        {

            return SamplerStatus.NoChange;

        }

        else if (res.Status == PromptStatus.OK)

        {

            _mTempPoint = res.Value;

            return SamplerStatus.OK;

        }

        return SamplerStatus.Cancel;

    }

 

    protected override bool Update()

    {

        try

        {

            Leader leader = Entity as Leader;

 

            Editor ed

                = Application.DocumentManager.MdiActiveDocument.Editor;

            if (_mIsJigStarted)

            {

                // Remove the last vertex since we are only jigging

                leader.RemoveLastVertex();

            }

 

            Point3d lastVertex

                    = leader.VertexAt(leader.NumVertices - 1);

            if (!_mTempPoint.Equals(lastVertex))

            {

                // Temporarily append the acquired point as a vertex

                leader.AppendVertex(_mTempPoint);

                _mIsJigStarted = true;

            }

        }

        catch (System.Exception ex)

        {

            Document doc

               = Application.DocumentManager.MdiActiveDocument;

            doc.Editor.WriteMessage("\nException: " + ex.Message);

            return false;

        }

        return true;

    }

 

    public void addVertex()

    {

        Leader leader = Entity as Leader;

 

        leader.AppendVertex(_mTempPoint);

 

        _mPts.Add(_mTempPoint);

    }

 

    public void removeLastVertex()

    {

        Leader leader = Entity as Leader;

        if (_mPts.Count >= 1)

        {

            leader.RemoveLastVertex();

        }

    }

 

    public Entity getEntity()

    {

        return Entity;

    }

 

    [CommandMethod("MYSL")]

    public static void MySplinedLeader()

    {

        Document doc

              = Application.DocumentManager.MdiActiveDocument;

        Editor ed = doc.Editor;

        Database db = doc.Database;

 

        SplinedLeaderJig jig = new SplinedLeaderJig();

 

        bool bSuccess = true;

        bool bComplete = false;

 

        while (bSuccess && !bComplete)

        {

            SplinedLeaderJig._mIsJigStarted = false;

 

            PromptResult dragres = ed.Drag(jig);

 

            bSuccess = (dragres.Status == PromptStatus.OK);

            if (bSuccess)

                jig.addVertex();

 

            bComplete = (dragres.Status == PromptStatus.None);

            if (bComplete)

            {

                jig.removeLastVertex();

            }

        }

 

        if (bComplete)

        {

            // Append entity to DB

            Transaction tr

                    = db.TransactionManager.StartTransaction();

            using (tr)

            {

                BlockTable bt = tr.GetObject(

                        db.BlockTableId, OpenMode.ForRead

                                              ) as BlockTable;

                BlockTableRecord ms =

                    bt[BlockTableRecord.ModelSpace].GetObject

                    (OpenMode.ForWrite) as BlockTableRecord;

 

                ms.AppendEntity(jig.getEntity());

                tr.AddNewlyCreatedDBObject(jig.getEntity(),

                                            true);

                tr.Commit();

            }

        }

    }

Positioning a selected entity at view center

By Balaji Ramamoorthy

Here is a code snippet to position an entity at the center of the view. Most of this code is similar to the way we would zoom on to an entity except that the Width and Height of the view is not modified. In this case, it is only relevant to set the view center point in DCS.

Document doc = Application.DocumentManager.MdiActiveDocument;

Database db = doc.Database;

Editor ed = doc.Editor;

 

PromptEntityOptions peo

            = new PromptEntityOptions("\nSelect an entity:");

PromptEntityResult per = ed.GetEntity(peo);

if (per.Status != PromptStatus.OK)

    return;

 

ed.UpdateTiledViewportsInDatabase();

 

using (Transaction tr = db.TransactionManager.StartTransaction())

{

    Entity ent = tr.GetObject(

                    per.ObjectId, OpenMode.ForRead) as Entity;

 

    Extents3d entityExtent = ent.GeometricExtents;

 

    ViewportTable vpTbl = tr.GetObject(

                                        db.ViewportTableId,

                                        OpenMode.ForRead

                                      ) as ViewportTable;

 

    ViewportTableRecord viewportTableRec

           = tr.GetObject(vpTbl["*Active"], OpenMode.ForWrite)

                                       as ViewportTableRecord;

 

    Matrix3d matWCS2DCS

       = Matrix3d.PlaneToWorld(viewportTableRec.ViewDirection);

 

    matWCS2DCS = Matrix3d.Displacement(

        viewportTableRec.Target - Point3d.Origin) * matWCS2DCS;

 

    matWCS2DCS = Matrix3d.Rotation

                                (

                                 -viewportTableRec.ViewTwist,

                                 viewportTableRec.ViewDirection,

                                 viewportTableRec.Target

                                 ) * matWCS2DCS;

 

    matWCS2DCS = matWCS2DCS.Inverse();

 

    entityExtent.TransformBy(matWCS2DCS);

 

    Point2d center = new Point2d(

    (entityExtent.MaxPoint.X + entityExtent.MinPoint.X) * 0.5,

    (entityExtent.MaxPoint.Y + entityExtent.MinPoint.Y) * 0.5);

 

    viewportTableRec.CenterPoint = center;

 

    tr.Commit();

}

 

ed.UpdateTiledViewportsFromDatabase();

Resolving name conflict during XRef binding

By Balaji Ramamoorthy

Recently a developer reported a behavior that a few entities went missing after the external references in a drawing were bound using API. On analyzing the drawing and its external references, the reason for this strange behavior was a block definition with the same name being present in the host and in one of the XRef drawings.

Although the block definitions were different in the drawings, they shared the same name. When such XRef drawings are bound, this can result in block references using the block definition from the host drawing.

 If the "insertBind" parameter is set to false in the call to "BindXrefs", this should help resolve such name conflicts. Here is an explanation from acadauto.chm on how AutoCAD resolves such name conflicts during XRef binding :

If the bPrefixName parameter is set to FALSE, the symbol names of the xref drawing are prefixed in the current drawing with <blockname>$x$, where x is an integer that is automatically incremented to avoid overriding existing block definitions. If the bPrefixName parameter is set to TRUE, the symbol names of the xref drawing are merged into the current drawing without the prefix. If duplicate names exist, AutoCAD uses the symbols already defined in the local drawing. If you are unsure whether your drawing contains duplicate symbol names, it is recommended that you set bPrefixName to FALSE. 

 

Extracting IsoLines from Surface

By Balaji Ramamoorthy

Here is a sample code to extract IsoLines along the U and V directions of a surface. The extracted curves are added to the database.

// 1) Enable support for the BRep API in StdAfx.h

#define _BREP_SUPPORT_            //- Support for the BRep API

 

// 2) Code to retrieve the IsoLines from a surface

Acad::ErrorStatus es;

 

ads_point pt;

ads_name ename;

if (RTNORM != acedEntSel(L"Select a Surface", ename, pt))

    return;

 

AcDbEntity *pEnt = NULL;

AcDbObjectId id;

es = acdbGetObjectId(id, ename);

es = acdbOpenAcDbEntity(pEnt, id, AcDb::kForWrite);

AcDbSurface *pSurface = AcDbSurface::cast(pEnt);

if(NULL == pSurface)

{

    acutPrintf(ACRX_T("\nPlease select a surface."));

    return;

}

 

AcDbNurbSurfaceArray nsArray;

es = pSurface->convertToNurbSurface(nsArray);

if(es == Acad::eOk)

{

    if(nsArray.length() == 1)

    {

        AcDbDatabase *pDb

            = acdbHostApplicationServices()->workingDatabase();

 

        AcDbBlockTable *pBlockTable = NULL;

        es = pDb->getBlockTable(pBlockTable, AcDb::kForRead);

 

        AcDbBlockTableRecord *pMS = NULL;

        es = pBlockTable->getAt(

                       ACDB_MODEL_SPACE, pMS, AcDb::kForWrite);

 

        AcDbNurbSurface *pNS = NULL;

        pNS = AcDbNurbSurface::cast(nsArray.at(0));

 

        Adesk::UInt16 uIsoDensity = pSurface->uIsolineDensity();

        Adesk::UInt16 vIsoDensity = pSurface->vIsolineDensity();

 

        AcDbBody* pBody = new AcDbBody();

 

        es = pBody->setASMBody(pSurface->getLockedASMBody());

 

        AcBr::ErrorStatus ebs;

        AcBrBrep* pBrep = new AcBrBrep();

        ebs = pBrep->set(*pBody);

        if(AcBr::eOk == ebs)

        {

            AcBrBrepFaceTraverser* pFaceTrav

                                = new AcBrBrepFaceTraverser;

            ebs = pFaceTrav->setBrep(*pBrep);

            if(AcBr::eOk == ebs)

            {

                for(pFaceTrav->restart();

                        !pFaceTrav->done();pFaceTrav->next())

                {

                    AcBrFace face;

                    ebs = pFaceTrav->getFace(face);

                    if(AcBr::eOk == ebs)

                    {

                        AcGeSurface *pGeSurface;

                        ebs = face.getSurface(pGeSurface);

 

                        Adesk::Boolean isClosedInU

                                  = pGeSurface->isClosedInU();

 

                        Adesk::Boolean isClosedInV

                                  = pGeSurface->isClosedInV();

 

                        int ucMax = uIsoDensity+2;

                        if(isClosedInU)

                            ucMax = uIsoDensity;

 

                        int vcMax = vIsoDensity+2;

                        if(isClosedInV)

                            vcMax = vIsoDensity;

 

                        AcGeInterval intervalU, intervalV;

                        pGeSurface->getEnvelope

                                       (intervalU, intervalV);

 

                        double boundMinU = 0.0,

                               boundMaxU = 0.0,

                               boundMinV = 0.0,

                               boundMaxV = 0.0;

 

                        intervalU.getBounds

                                       (boundMinU, boundMaxU);

 

                        intervalV.getBounds

                                       (boundMinV, boundMaxV);

 

                        double paramIncrU =

                        (boundMaxU - boundMinU) /

                        (isClosedInU ? uIsoDensity :

                                       (uIsoDensity+1));

 

                        double paramIncrV =

                        (boundMaxV - boundMinV) /

                        (isClosedInV ? vIsoDensity :

                                       (vIsoDensity+1));

 

                        double paramU = boundMinU;

                        for(int uc = 0; uc < ucMax; uc++)

                        {

                            double paramV = boundMinV;

                            for(int vc = 0; vc < vcMax; vc++)

                            {

                                AcArray<AcDbCurve*> uIsoLines;

                                es = pNS->getIsolineAtU(

                                           paramU, uIsoLines);

 

                                if(es == Acad::eOk)

                                {

                                    for(int cnt = 0;

                                        cnt < uIsoLines.length();

                                        cnt++)

                                    {

                                        AcDbCurve *pCurve

                                            = uIsoLines[cnt];

 

                                        pCurve->setColorIndex(1);

 

                                        pMS->appendAcDbEntity

                                                     (pCurve);

 

                                        pCurve->close();

                                    }

                                }

 

                                AcArray<AcDbCurve*> vIsoLines;

                                es = pNS->getIsolineAtV(

                                           paramV, vIsoLines);

 

                                if(es == Acad::eOk)

                                {

                                    for(int cnt = 0;

                                        cnt < vIsoLines.length();

                                        cnt++)

                                    {

                                        AcDbCurve *pCurve

                                             = vIsoLines[cnt];

 

                                        pCurve->setColorIndex(1);

 

                                        pMS->appendAcDbEntity

                                                     (pCurve);

 

                                        pCurve->close();

                                    }

                                }

 

                                paramV += paramIncrV;

                            }

                            paramU += paramIncrU;

                        }

                    }

                    else

                    {

                        acutPrintf(

                              ACRX_T("\nSorry, BRep error."));

 

                        break;

                    }

                }

            }

            else

            {

                acutPrintf(ACRX_T("\nSorry, BRep error."));

            }

 

            delete pFaceTrav;

        }

        else

        {

            acutPrintf(ACRX_T("\nSorry, BRep error."));

        }

 

        delete pBrep;

 

        es = pMS->close();

        es = pBlockTable->close();

    }

    else

    {

        acutPrintf(ACRX_T("\nSorry, this code cannot handle

                               multiple Nurb surfaces yet."));

    }

 

    // Cleanup

    for(int cnt = 0; cnt < nsArray.length(); cnt++)

    {

        AcDbNurbSurface *pNS = NULL;

        pNS = AcDbNurbSurface::cast(nsArray.at(cnt));

        if(pNS != NULL)

        {

            delete pNS;

        }

    }

}

else

{

    acutPrintf(

        ACRX_T("\nSorry, could not convert to Nurb surface."));

}

 

pSurface->close();

Here is a screenshot of the IsoLines extracted from a revolved surface