## Use Lapack In Eigen To Compute SVD In CPP Project

OS: Ubuntu 22.04.2 LTS. Download eigen from website: https://eigen.tuxfamily.org/index.php?title=Main_Page Small Eigen Project Write a file main.cpp which use eigen library. Build and run it. Use Lapack In Eigen In C++ Project Write test code to use lapack, build and run the project. Create a file matrix.txt Run the executable file by Read more…

## SVD And Eigenvector

The eigenvector of a linear transformation doesn’t change in the transformation, and the scale of this vector under the transformation is called the eigenvalue. Practice We use 3D Model Editor to perform the following linear transformation: For more information on how to use the web app 3D Model Editor to Read more…

## Flip Item – Mirror Symmetry

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…

## The Potential Risk In vtkTransform::Inverse

I found a bug when we do matrix inverse calculation by vtkTransform object. The version 8.2.0 and 9.1.0 of VTK has the same potential risk in vtkMatrix4x4::Invert(const double inElements[16], double outElements[16]).Let’s see the source code, it judges whether the determinant value is zero by ==. The equal comparison operation for Read more…

## The Geometry Meaning Of The Determinant

The geometry meaning of the determinant is the sign volumn value for three vectors in 3D world or a sign area value of two vectors (parallelogram) in the 2D coordinate system. For three points in the 2D world:     The triangle is counterclockwise ordered if and clockwise ordered if Read more…

## VTK : Find The Intersect Point Of Three Planes In The 3D Space

I want to find the inner polydata which are surrounded by six planes in the above image. So the intersect point of the three planes that intersect is important. How to find the intersect point of the three planes? We know the mathematical expression for a plane has the following Read more…

## Use Local Coordinate System And Show It

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…

## Remove The Previous Change Of Model

There are three adjustment stages of the cone in our test. : rotate the cone and make it bigger. : translate the cone after : translate the cone from the original position.             Original Scene Create an initial scene like the following image. The red Read more…

## Make Model Moving On The Surface

The article shows how to move a model on the surface of the other big one.I planed to move the cube on the surface of a big superquadric in the mouse left press moving event. Let’s build an original scene. Created a superquadric source object in ParaView and saved it Read more…

Tex To PDF
: convert the Latex file which suffix is tex to a PDF file

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