There are two projection methods for camera setting, orthographic (paraller) projection and perspective projection, they have different view styles. The light of sight in orthographic (paraller) projection is just like the light of sun. So the segment length keeps same at far and near position. The model’s size is is Read more…
I had found a crash bug when use vtkContourWidget by webassembly in the post Crash Bug About vtkOpenGLPolyDataMapper::UpdateShaders In vtkAbstractWidget.As we know, SetResolveCoincidentTopologyToPolygonOffset for mapper can make web page crash, related post: The Interfaces In VTK Can’t Be Used With Webassembly. After reading the source code of vtkOrientedGlyphContourRepresentation::vtkOrientedGlyphContourRepresentation(), we know Read more…
The Interfaces In VTK Can’t Be Used With Webassembly Setting point size and line width doesn’t work vtkProperty.h Shift polygons, lines and points will fail in wasm. It will cause crash on web page. The new polydata generated by vtkFeatureEdge algorithm can’t be rendered in WebGL because something is wrong Read more…
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…