Hatch a region,appendLoop return eInvalidInput

[dziwve67853]

Acad::ErrorStatus es;

ads_name ename;ads_point pt;

if(RTNORM==acedEntSel(_T("\nPlease select a region:"),ename,pt))

{

acutPrintf(_T("\nError!"));return;

}

AcDbObjectId id;

acdbGetObjectId(id,ename);

AcDbObjectIdArray objIds;

objIds.append(id);

AcDbHatch *pHatch=new AcDbHatch();

AcGeVector3d normal(0,0,1);

pHatch->setNormal(normal);

pHatch->setElevation(0);

pHatch->setPattern(AcDbHatch::kPreDefined,_T("SOLID"));

es=pHatch->appendLoop(AcDbHatch::kExternal,objIds);

assert(Acad::eInvalidInput== es);

es=pHatch->evaluateHatch();

postToDb(db, pHatch);

I have chosen a region and want to create a Hatch based on it, but appendLoop cannot return Acad:: eOk.Why?

@tbrammer @Alexander.Rivilis 

[tbrammer]

The region consists of two separate closed paths. I think appendLoop(Adesk::Int32, const AcDbObjectIdArray&) can only append exactly one loop each time. You could _EXPLODE the region to split it into two separate regions and create hatches in both of them.

If you want to keep the region you can extract the bounding geometries and use the other appendLoop() methods:

    Acad::ErrorStatus appendLoop(Adesk::Int32 loopType,
                                 const AcGeVoidPointerArray& edgePtrs,
                                 const AcGeIntArray&  edgeTypes);

    Acad::ErrorStatus appendLoop(Adesk::Int32 loopType,
                                 const AcGePoint2dArray& vertices,
                                 const AcGeDoubleArray& bulges);

But you won't be able to create an associative hatch like this.

The only possible way to get associativity seems to be this function in aced.h:

Acad::ErrorStatus 
acedConvertEntityToHatch(AcDbHatch* pHatch, AcDbEntity*& pEnt, bool transferId);

I never used this API and it seems to be tricky to handle.

[dziwve67853 · Accepted solution]

acedCommand(RTSTR, TEXT("-HATCH"),RTSTR, _T("S"), RTENAME, regionName, RTSTR, _T(""), RTSTR, _T(""), RTNONE);

It is possible to convert a region to a Hatch using the lsp command. I am not sure how the lsp command is implemented internally.