I can’t display vtkContourWidget object on web page by wasm file.The following code snippet is very simple, create a circle and show it, we can modify it by vtkContourWidget object.The example works in CPlusCPlus program.VTK version: 9.0.2. But it will crash on our web page. Output: It seems something wrong Read more…
The post shows how to use VTK to display 3D model with shading.We need to make sure the version of VTK is equal to 9 or bigger than it.To avoid the faceted appearance, compute points’ normal to support to has shading at triangle vertices. Demo: Output: The faceted surface of Read more…
The post is related to The Example About vtkPolyDataNormals. If you want to use vtkPolyDataNormals to compute the normals of points, it’s better to set variable Splitting false. #include <vtkVersion.h> #include <vtkSmartPointer.h> #include <vtkSurfaceReconstructionFilter.h> #include <vtkProgrammableSource.h> #include <vtkContourFilter.h> #include <vtkReverseSense.h> #include <vtkPolyDataMapper.h> #include <vtkProperty.h> #include <vtkPolyData.h> #include <vtkCamera.h> #include <vtkRenderer.h> Read more…
We can use vtkTransform’s function concatenate to do matrix multiplication. There are three matrix which have the mathematical relationship. It’s equivalent to the following code. vtkSPtrNew( C, vtkTransform ); C->Concatenate(B); C->Concatenate(A); C->Update(); The experimental code: #include <iostream> #include <vtkSmartPointer.h> #include <vtkTransform.h> #define vtkSPtr vtkSmartPointer #define vtkSPtrNew(Var, Type) vtkSPtr<Type> Read more…
We have to clear actors in vtkCellPicker object before InitializePickList. In the function Pick, the picker object will addItem to increase its reference count. So we need to do the following tasks for picker object in class destructor function to avoid crash or weird visible bug.
The post shows how to generate an oriented bounding box based on the three axis known in advance. The 3D model is displayed by a CUModel object. We will calculate the two farthest points, positive farthest point and negative farthest point along the special direction. Then generate a polydata from Read more…
As we know, we can create a linear transform to change model to the special orientation and position. Refer to The Releationship Between Local Transform And Pose Transform. Let’s define orientation and position by three axis and point. , , and origin = . The matrix for the linear transform Read more…
Here is a example that vtkTransform object failed to deep copy the other one. #include <iostream> #include <vtkSmartPointer.h> #include <vtkRenderer.h> #include <vtkRenderWindow.h> #include <vtkTransform.h> #define vtkSPtr vtkSmartPointer #define vtkSPtrNew(Var, Type) vtkSPtr<Type> Var = vtkSPtr<Type>::New(); int main() { setbuf( stdout, nullptr ); vtkSPtrNew( trans, vtkTransform ); auto matrix = trans->GetMatrix(); matrix->SetElement( Read more…
You can use the key ‘i’ to enable or disable the vtkSliderWidget object defaultly. Here is a post about how to use vtkSliderWidget to control other model, Control The Size Of Model By VtkSliderWidget. But we don’t want the shortcut key to influence the program UI sometimes. So let’s forbid Read more…