Substraction between one volume respect other two volumes does not affect the intersected areas

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1

Hello,

I have a doubt I hope someone can give me an idea. I want to substract one volume (obtained from a polydata with vtkPolyDataToImageStencil) from several cubes which are polydatas too. I append the cubes with vtkAppendPolyData to make a single substraction and i also transform it into volume. And i make a boolean substraction . The substracion in the areas with cubes that are intersecting the substraction is not applied. I solved it by substracting each cube one by one to the volume but it becomes slower. I wonder how the filters treat the intersected areas. I don´t want to do this operation with polydatas because i have many problems clipping and closing surfaces because the data can come with many issues.

Thank you very much

intersection

2

Do you have any code and sample files for us?

3

Sure, here it is:

vtkSmartPointer<vtkPolyDataCollection > allCylindersRed = widget_mgr_.lock()->getAllCylindersOfImplantActor(0); //0 => RED CYLINDER
vtkSmartPointer<vtkAppendPolyData> appendFilterRedCylinders = vtkSmartPointer<vtkAppendPolyData>::New();
//Create a polydata with all the implants for the boolean
for (allCylindersRed->InitTraversal();
	vtkPolyData* PolyData = allCylindersRed->GetNextItem();) {
	//Append the two meshes
	appendFilterRedCylinders->AddInputData(PolyData);
	appendFilterRedCylinders->Update();
}

  vtkSmartPointer<vtkImageData> RedCylinders_img =   getFromPolydataToImage(appendFilterRedCylinders->GetOutput(), final_bounds);

  extrude_WithoutRedCylinders_img =    booleanSubstractionTwoPolyDatas(extrude, RedCylinders_img );

vtkSmartPointer<vtkImageData> booleanSubstractionTwoPolyDatas(vtkSmartPointer<vtkImageData> extrude1, vtkSmartPointer<vtkImageData> extrude2) {

}

//Substract one image from the other
vtkSmartPointer<vtkImageMathematics> boolean = vtkSmartPointer<vtkImageMathematics>::New();
boolean->SetInput1Data(extrude1);
boolean->SetInput2Data(extrude2);
boolean->SetOperationToSubtract();
boolean->Update();


return boolean->GetOutput();
}
4

Using images for a boolean operation is often a very bad idea. What’s with vtkBooleanOperationPolyDataFilter or https://github.com/zippy84/vtkbool?

5

Thanks for answering. I tried it but it was very slow

6

Could you please provide your polydatas!

7

Hi, here you have the stl and i tried to substract a cylinder and it takes a long time.

Thanks

8

@zandarina One stl is not enough. Where is the cylinder?

9

Hello, thanks for answering i use this piece of code for the cylinder and i move it with a bounding box and i initialize it with the position of the mouse

cylinder->SetHeight(height_red_cyl);
const double red_radius = implant->GetHoleDiameter() / 2;
cylinder->SetRadius(red_radius);
cylinder->SetResolution(100);
//cylinder->Update();
//cylinder->SetAxis(0, 1, 0);

//Cylinder red
vtkNew<vtkPolyDataMapper> mapper;
mapper->SetInputConnection(cylinder->GetOutputPort());
mapper->Update();
vtkNew<vtkActor> actor_cylinder;
actor_cylinder->SetMapper(mapper);
actor_cylinder->GetProperty()->SetColor(1, 0, 0);
actor_cylinder->GetProperty()->SetOpacity(0.5);

thanks

10

I need two stl’s or vtk’s! I don’t know your parameters. Try to export one of you cylinders.

11

sure, i have added the polydatas to make the substraction

Thanks

12

There is no contact:

Bildschirmfoto_2020-03-17_19-59-07
Bildschirmfoto_2020-03-17_19-59-07734Ă—637 26.8 KB

13

Hi sorry i don´t understand why it did not apply the transformation. I checked the vtk files and both polydatas intersect. I hope it is ok this time.

Thanks

14

With my filter you will get this result:

Bildschirmfoto_2020-03-18_18-22-41
Bildschirmfoto_2020-03-18_18-22-41613Ă—563 87.1 KB

15

Awesome results. How long did it take? Is the result a closed surface?.

Thanks for trying and congrats for your library

16

Only a few milliseconds…

Just apply CleanPolyData and you will have one surface.

17

Hi, I am trying to use your library as you suggested but when i try to susbtract two polydatas to empty the extruded stl, it goes very slow. How can i speed up the susbstraction?. Thank you very much

vtkNew<vtkSTLReader> reader;
reader->SetFileName("filename.stl");
reader->Update();


///// 1
/////// extrude towards height to make the hole
vtkSmartPointer<vtkLinearExtrusionFilter> extrude =
	vtkSmartPointer<vtkLinearExtrusionFilter>::New();
extrude->SetInputData(reader->GetOutput());
extrude->SetExtrusionTypeToVectorExtrusion();
extrude->SetVector(0, 0, 1);
extrude->SetScaleFactor(5.2);
extrude->Update();






///// 2

// Make the basis
vtkSmartPointer<vtkPolyDataNormals> normals2 =
	vtkSmartPointer<vtkPolyDataNormals>::New();
normals2->SetInputData(reader->GetOutput());
normals2->ConsistencyOn();
normals2->SetComputeCellNormals(1);
normals2->SplittingOff();
normals2->Update();



/////// original cut /////
vtkSmartPointer<vtkLinearExtrusionFilter> extrude2 =
	vtkSmartPointer<vtkLinearExtrusionFilter>::New();
extrude2->SetInputData(normals2->GetOutput());
extrude2->SetExtrusionTypeToNormalExtrusion();
//extrude->SetVector(0, 0, -1);
extrude2->SetScaleFactor(3.0);
extrude2->Update();



vtkPolyDataBooleanFilter *bf2 =   
  vtkPolyDataBooleanFilter::New();
bf2->SetInputConnection(0, extrude->GetOutputPort());
bf2->SetInputConnection(1, extrude2->GetOutputPort());
bf2->SetOperModeToDifference();
bf2->Update();

vtkSmartPointer<vtkPolyDataMapper> Mapper4 =
	vtkSmartPointer<vtkPolyDataMapper>::New();
Mapper4->SetInputData(bf2->GetOutput());
Mapper4->ScalarVisibilityOff();

vtkSmartPointer<vtkActor> Actor4 =
	vtkSmartPointer<vtkActor>::New();
Actor4->SetMapper(Mapper4);
Actor4->GetProperty()->SetColor(0, 0, 1);




// Create renderers and add actors of plane and cube
vtkSmartPointer<vtkRenderer> renderer =
	vtkSmartPointer<vtkRenderer>::New();


renderer->AddActor(Actor4); 


vtkSmartPointer<vtkRenderWindow> renderWindow =
	vtkSmartPointer<vtkRenderWindow>::New();
renderWindow->AddRenderer(renderer);
renderWindow->SetSize(600, 600);

vtkSmartPointer<vtkRenderWindowInteractor> interactor =
	vtkSmartPointer<vtkRenderWindowInteractor>::New();
interactor->SetRenderWindow(renderWindow);
renderer->SetBackground(0, 0, 0);
renderWindow->Render();

interactor->Start();
18

Hi, one last question, I was thinking again about the booleans you suggested me by now I have it all in volume operations and I got a decent result. But I am thinking that combining both options it can be a good idea to obtain even a better polydata.

But I was wondering in the picture you show why the bottom of the cylinder is not removed from the output of the boolean operation substraction. The result should be a hole. I does not make sense to me. I also got the same issue with the substraction of the polydata with the cylinder.

Thanks

Screenshot_1

19

I found that this is caused in debug but not a release. Amd the vtkAppendPolyData if there is intersection does not work eaither. But I fixed it doing one by one. I will look into the vtkAppendPolyData to see what’s wrong with this filter in the intersections. If I find it out I will let you know because it happens in volume and polydata in boolean operations. Thanks

20

Here I have two meshes, I used vtkbool library(GitHub - zippy84/vtkbool: A new boolean operations filter for VTK) to get the result of which the operation of boolean difference, but the result modes have some errors, like holes. I want to known how to solve the problem?Thanks a lot.
A.stl (684 Bytes)
B.stl (61.0 KB)
result.stl (82.0 KB)

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