cap a vtkClipPolyData does not work propertly. Weird behaviour

Support
1

Hi i´d like to cap the parts i clip and i used the code of this example

http://www.vtk.org/Wiki/VTK/Examples/Cxx/Meshes/CapClip

And i also tried this:

		for (int i = 0; i < (int)clipFilters_.size(); i++) {

			clipFilters_[i]->SetClipFunction(boolean_opsEahcPlane[i]);
			clipFilters_[i]->InsideOutOn();
			clipFilters_[i]->Update();
			clipFilters_[i]->Modified();

		}
		

		// Now extract feature edges
		auto boundaryEdges = vtkSmartPointer<vtkFeatureEdges>::New();
		boundaryEdges->SetInputConnection(clipFilters_[clipFilters_.size() - 1]->GetOutputPort());
		boundaryEdges->BoundaryEdgesOn();
		boundaryEdges->FeatureEdgesOff();
		boundaryEdges->NonManifoldEdgesOff();
		boundaryEdges->ManifoldEdgesOff();

		auto boundaryStrips = vtkSmartPointer<vtkStripper>::New();
		boundaryStrips->SetInputConnection(boundaryEdges->GetOutputPort());
		boundaryStrips->Update();

		// Triangulate the polyline contour
		vtkSmartPointer<vtkContourTriangulator> triangulator =
			vtkSmartPointer<vtkContourTriangulator>::New();
		triangulator->SetInputConnection(boundaryStrips->GetOutputPort());
		triangulator->Update();


		vtkSmartPointer<vtkAppendPolyData> appendFilter =
			vtkSmartPointer<vtkAppendPolyData>::New();
		appendFilter->AddInputConnection(triangulator->GetOutputPort());
		appendFilter->AddInputConnection(clipFilters_[clipFilters_.size() - 1]->GetOutputPort());

		// Remove any duplicate points.
		vtkSmartPointer<vtkCleanPolyData> cleanFilter =
			vtkSmartPointer<vtkCleanPolyData>::New();
		cleanFilter->SetInputConnection(appendFilter->GetOutputPort());
		cleanFilter->Update();
		
		 
                    Actor->GetMapper()->SetInputConnection(cleanFilter->GetOutputPort());
		Actor->GetMapper()->Update();

but it does not work for me. I get a weird behaviour. Is there any other fiter to close the gaps or to clip with cap?. Thanks

clip_empty
clip_empty874×513 253 KB

cap_clipping

2

Can you reduce de scene complexity? I mean, try to clip a simple triangulated sphere with your code and try to get the same unexpected behavior. The likelyhood of diagnosing bugs is far greater when we reproduce the problem with simpler data.

3

If you’re using a plane there is something specifically for closing while clipping. “vtkClipClosedSurface”. This requires manifold input (closed/watertight and non intersecting faces). It will also generate an open face if the normals or winding is backward. Use vtkReverseSense to fix that.

1 Like
4

Sure, but i cannot always guarantee manifold input and I have boolean operations not only planes i also get weird results with vtkClipClosedSurface. I have solved it transforming to volume to close it. But it is slower.

Thanks for the suggestions