We have to calculate the vector on the special direction firstly. void CalculateVecComponent(PointStruct originVec, PointStruct &axis0, PointStruct &vecOnAxis) { double cosTheta = originVec.Dot( axis0 ); return axis0*cosTheta; } Project point on line Point GetProjectPtOnDir(Point pt, Point dir, Point startPt) { dir.Unit(); Point ptVector = pt – startPt; double cosTheta = Read more…
I had built VTK-8.1.1 and Qt5.12.1. After installing pyqt, I wrote a simple project and run it, the error message showed that it needs the newer version of Qt 5.15. So I download Qt-5.15.1 from https://download.qt.io/archive/qt , build it, and install all libraries. I didn’t find QtCreator app, therefore I Read more…
Create two half spheres and save them in a vtp file by ParaView. We will use it to explore an algorithm that finds the two separated cut list and sort all points in every list. The original scene is like the following images. Use vtkCutter to create cut lines that Read more…
I want to change the camera’s position and focal point to focus on a small region on the surface of the sphere. The parameters viewUp direction, focal point, position, and parallel scale are important for our target. Our scene comes from a previous article VTK – Find Partial Region And Read more…
How to create a local coordinate system and show it? We define the local coordinate system has its own x-axis, y-axis, z-axis, and origin. We call the left coordinate system L1 and the right coordinate system L2. Regard L1 as the world coordinate system in VTK, the other one L2 Read more…
We can use vtkButtonWidget to create 2D buttons in the render window. The vtkWidgetRepresentation object controls the button’s position and show button pictures. Write our class ButtonCallBack that inherits vtkCommand and use it to listen for vtkCommand::StateChangedEvent, then we can add our button click function in it. Finally, the widget Read more…
Find a local partial region on the surface of the sphere, mark it by red color. Finally, we will compute the normal of the partial region and show it by a green line. The whole scene is just like the following image. Here are a few steps about the process. Read more…
Create a sphere and clip it as the following image. We will pull down the boundary and close the opening to get a new model. How to pull down the boundary of the hemispheres? Step 1. Find all independent edges which are used by only one cell. Step 2. Connect Read more…
The interface vtkObjectBase::UnRegister will reduce the reference count for pointer and delete the pointer if the reference count becomes zero. vtkObjectBase::Delete <= vtkObjectBase::UnRegister <= vtkObjectBase::UnRegisterInternal <= delete ptr vtkSmartPointerBase::~vtkSmartPointerBase { vtkObjectBase* object = this->Object; if(object) { this->Object = nullptr; object->UnRegister(nullptr); } } We can get the reference count and consumer Read more…