The article introduces how to expand the sampling area from a cell. I marked the area red color, the center point is computed as the mass center of the original cell. Step 1, find all cells which are near to the center point within a distance. We can use the Read more…
I wanted to find the area in the black circle on the tooth surface, so the algorithm class vtkSelectPolyData was used in my project. The idealized result looks like the following picture. Unfortunately, I got the bad region as this scene. After reading the source code about vtkSelectPolyData, I found Read more…
We create a simple scene for the first time, cone and axes are in the point (0, 0, 0). #include <iostream> #include <vtkSmartPointer.h> #include <vtkSphereSource.h> #include <vtkActor.h> #include <vtkConeSource.h> #include <vtkRenderer.h> #include <vtkRenderWindow.h> #include <vtkPolyDataMapper.h> #include <vtkLineSource.h> #include <vtkRenderWindowInteractor.h> #include <vtkAxesActor.h> #include <vtkProperty.h> #include <vtkXMLPolyDataReader.h> #include <vtkCharArray.h> #include <vtkPointData.h> #include Read more…
This post introduces a way to find the biggest plane on the 3D model. We expand the initial cell by comparing its normal with neighbor’s normal. It indicates they are on a plane if the two normals of cells are approximately equal. I use vtkOBBTree to find the min axes Read more…
Step function The step function is simple, it gets only two values zero or one no matter what the input value is. #!/usr/bin/env python import numpy as np import matplotlib.pylab as plt def step_function(x): return np.array(x>0, dtype=np.int) if __name__ == ‘__main__’: x = np.arange( -5, 5, 0.1 ) y = Read more…
Creating Factory We often make_shared to create a shared pointer in std. It’s safe and easy for the developer to use. The using examples are in the following code snippet. shared_ptr<Base> ptr = make_shared<Base>(); auto p = make_shared<int>(100); cout << *p << endl; Delete Function Create a delete function for Read more…
C++11 supports the flexible parameter list by template technology, it can help us to define a powerful function. The article introduces how to create a log output function which looks like the following scene. Log( IDebug, “one: “, 1, “, two: “, 2, “, three: “, 3 ); The first Read more…
The article introduces how to collect Chinese idioms on the Internet by python. I chose a website that contains many Chinese idioms, http://cy.5156edu.com , to do the experiments. We have to make sure the library BeautifulSoup installed for Python firstly, it can help us to analyze the web page. Maybe Read more…
The article introduces two ways to calculate the distance from a point to a line. One use dot product by two vectors to get distance vector, and the other use cross product by vectors to achieve it. Let’s assume the point is P, two endpoints of the line are L1 Read more…