Extract bag plot filter is not using the most adequate 2D kernel density estimation.
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
In Paraview, HDR plot uses a 2D kernel density estimation in the plane associated to the first 2 principal components. In Paraview, a symmetrical normal kernel is used and its width, given by the user, is by default equal to 1. This 2D density approximation is not accurate.
In the Rainbow package, the method used is the kernel density estimation is based on a generic Gaussian not necessarily symmetrical. In addition, kernel's parameters (i.e. the covariance matrix) are determined by crosschecking (implying a optimization)
To validate this functionality, the "gaussian sine" case can be used.