PCL: Normal estimation or visualization not working - c++

Question

I am trying to start working with PCL and do this basic example:
https://pcl.readthedocs.io/projects/tutorials/en/latest/how_features_work.html#how-3d-features-work
However, either the normal estimation or the visualization of the estimated normals doesn't work as it should.
As some test data, I generated this simple mesh in Blender:
I am using this test object because I have some point cloud data that was recorded with a real 3D-LIDAR sensor that is more complex so just for the sake of resolving this issue, I am using this simpler object here.
I convert this mesh into a PCL point cloud and that also works well.
Here is the view of the built in PCL point cloud visualizer:
However, after doing a surface normal estimation and trying to visualize it, the result is very crude:
I would have expected a view similar to the normal point cloud visualization, since I passed the original point cloud AND the normals, however I only get eleven (I counted them) normals of which some of them don't even seem to point in the right direction and no visualization of the original point cloud either.
The point cloud has 1024 points in it and the estimated normal set also has 1024 estimated normals in it so I am not sure what is going wrong here.
I ran this program with different parameters for the Sphere-Radius search (0.03, 0.06, 0.3, 0.6, 1, 3) but got similar results.
Here is my code:
int main()
{
PointCloud<PointXYZ> cloud;
PointCloud<PointXYZ>::Ptr cloud_ptr(&cloud);
string filename = "C:\\Users\\ilmu0\\Desktop\\Blendertestobjects\\planeconcave.obj";
int readresult = OBJReader::readPointCloudFromFile(filename, cloud_ptr); //My own class which reads Blender ".obj" files
if (readresult != 0)
{
cout << "File could not be read" << endl;
return 1;
}
cout << "Cloud size: " << cloud.size() << endl; // --> 1024
NormalEstimation<PointXYZ, Normal> estimation;
estimation.setInputCloud(cloud_ptr);
KdTree<PointXYZ>::Ptr tree_ptr(new KdTree<PointXYZ>());
estimation.setSearchMethod(tree_ptr);
PointCloud<Normal>::Ptr normalCloud_ptr(new PointCloud<Normal>());
estimation.setRadiusSearch(0.6);
estimation.compute(*normalCloud_ptr);
cout << "Normals: " << normalCloud_ptr->size() << endl; // --> 1024
string result;
cin >> result;
//This is used to visualize the original point cloud only
//CloudViewer viewer("Simple Cloud Viewer");
//viewer.showCloud(cloud_ptr);
//while (!viewer.wasStopped())
//{
//}
PCLVisualizer viewer("PCL Viewer");
viewer.setBackgroundColor(0.0, 0.0, 0.5);
viewer.addPointCloudNormals<PointXYZ, Normal>(cloud_ptr, normalCloud_ptr);
while (!viewer.wasStopped())
{
viewer.spinOnce();
}
return 0;
}