Explanation

• Create a visualization window.

• Show coordinate axes in the window using CoordinateSystemWidget.

• Display a line representing the axis (1,1,1).

• Construct a cube.

• Create rotation matrix from rodrigues vector

• Use Affine3f to set pose of the cube.

• Animate the rotation using wasStopped and spinOnce

Code

#include <opencv2/viz/vizcore.hpp>#include <opencv2/calib3d/calib3d.hpp>#include <iostream>using namespace cv;using namespace std;/** * @function main */int main(){    /// Create a window    viz::Viz3d myWindow("Coordinate Frame");    /// Add coordinate axes    myWindow.showWidget("Coordinate Widget", viz::WCoordinateSystem());    /// Add line to represent (1,1,1) axis    viz::WLine axis(Point3f(-1.0f,-1.0f,-1.0f), Point3f(1.0f,1.0f,1.0f));    axis.setRenderingProperty(viz::LINE_WIDTH, 4.0);    myWindow.showWidget("Line Widget", axis);    /// Construct a cube widget    viz::WCube cube_widget(Point3f(0.5,0.5,0.0), Point3f(0.0,0.0,-0.5), true, viz::Color::blue());    cube_widget.setRenderingProperty(viz::LINE_WIDTH, 4.0);    /// Display widget (update if already displayed)    myWindow.showWidget("Cube Widget", cube_widget);    /// Rodrigues vector    Mat rot_vec = Mat::zeros(1,3,CV_32F);    float translation_phase = 0.0, translation = 0.0;    while(!myWindow.wasStopped())    {        /* Rotation using rodrigues */        /// Rotate around (1,1,1)        rot_vec.at<float>(0,0) += CV_PI * 0.01f;        rot_vec.at<float>(0,1) += CV_PI * 0.01f;        rot_vec.at<float>(0,2) += CV_PI * 0.01f;        /// Shift on (1,1,1)        translation_phase += CV_PI * 0.01f;        translation = sin(translation_phase);        Mat rot_mat;        Rodrigues(rot_vec, rot_mat);        /// Construct pose        Affine3f pose(rot_mat, Vec3f(translation, translation, translation));        myWindow.setWidgetPose("Cube Widget", pose);        myWindow.spinOnce(1, true);    }    return 0;}

OpenCV Tutorials —— Pose of a widget