[MSCE C++]Mesh面片拖拽相关的API

Question

请问MS update13 的SDK中有没有拖拽面片相关的API可以用？类似于MS ce版本中的Drag mesh功能。我想选中一个mesh网格中的几个面片然后对这几个面片进行处理。

Yongan.Fu · Answer

给您提供一个我曾经写过的测试样例供参考： 
 void meshQuery(WCharCP unparsed)
 {
 ElementHandle eh(849L, ACTIVEMODEL);
 if (!eh.IsValid())
 {
 mdlDialog_dmsgsPrint(L"invalid element id");
 return;
 }
 auto meshQuery = dynamic_cast<IMeshQuery*>(&eh.GetHandler());
 if (nullptr == meshQuery)
 return;
 
 PolyfaceHeaderPtr pMesh;
 meshQuery->GetMeshData(eh, pMesh);
 size_t numVertex, numFacet, numQuad, numTriangle, numImplicitTriangle, numVisEdges, numInvEdges;
 pMesh->CollectCounts(numVertex, numFacet, numQuad, numTriangle, numImplicitTriangle, numVisEdges, numInvEdges);
 WPrintfString myStr(L"mesh style = %d, numVertex = %d, numFacet = %d, numQuad = %d, numTriangle = %d",
 pMesh->GetMeshStyle(), numVertex, numFacet, numQuad, numTriangle);
 mdlDialog_dmsgsPrint(myStr);

 PolyfaceVisitorPtr pv = PolyfaceVisitor::Attach(*pMesh);
 int nFace = 1;
 while (pv->AdvanceToNextFace())
 {
 myStr.Sprintf(L"------------ face %d ------------", nFace);
 mdlDialog_dmsgsPrint(myStr.GetWCharCP());
 BlockedVectorDPoint3dR pts = pv->Point();
 for (DPoint3d pt : pts)
 {
 myStr.Sprintf(L"x = %.2f, y = %.2f, z = %.2f", pt.x, pt.y, pt.z);
 mdlDialog_dmsgsPrint(myStr.GetWCharCP());
 }
 nFace++;
 }
 }

Yongan.Fu · Answer

可借助于类PolyfaceCoordinateMap下的AddVistorFace将满足条件的面添加到一个新的Mesh中从而过滤掉不要的点。这样是生成了一个新的Mesh，可将老的Mesh删除即可。详细使用参考如下代码。我只是简单地设置了一个DRange3d进行点的过滤。 
 void meshCopyFacets(WCharCP unparsed)
{
	//1 ---- Get a PolyfaceHeader from ElementId (without any error checking)
	ElementHandle eh(226L, ACTIVEMODEL);
	auto meshQuery = dynamic_cast<IMeshQuery*>(&eh.GetHandler());
	PolyfaceHeaderPtr pInMesh;
	meshQuery->GetMeshData(eh, pInMesh);

	//2 ---- Create a PolyfaceHeader and connect it to a PolyfaceCoordinateMap
	PolyfaceHeaderPtr pOutMesh = PolyfaceHeader::CreateVariableSizeIndexed();
	pOutMesh->CopyAllActiveFlagsFrom(*pInMesh);
	PolyfaceCoordinateMapPtr pfmap = PolyfaceCoordinateMap::Create(*pOutMesh);

	//3 ---- Filter facets into PolyfaceCoordinateMap
	DRange3d range = DRange3d::FromMinMax(-50000, 50000);
	PolyfaceVisitorPtr pv = PolyfaceVisitor::Attach(*pInMesh);
	while (pv->AdvanceToNextFace())
	{
 BlockedVectorDPoint3dR pts = pv->Point();
 for (DPoint3d pt : pts)
 {
 if (!range.IsContained(pt))
 {
 pfmap->AddVisitorFace(*pv);
 break;
 }
 }
	}

	//4 ---- Add output mesh into current model
	EditElementHandle eeh;
	pOutMesh->Triangulate(100);
	MeshHeaderHandler::CreateMeshElement(eeh, nullptr, *pOutMesh, true, *ACTIVEMODEL);
	eeh.AddToModel();
} 
 执行结果如下图所示，能够看到右侧的Mesh被剪去了一块。

[MSCE C++]Mesh面片拖拽相关的API

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