Hi, @kachlica. Thank you for the affirmation.
What is it in the attachment? Is it the mesh after selection of "Export cloth mesh"?
The aim of CSF is to classify ground and non-ground points, cloth mesh is exported only because of Daniel's curious ;). It shows the final status of the dropping cloth. It is like DEM but it is not DEM. It is hard for CSF to filter these spikes because it is hard to tell if it is a spike or a detailed feature. I have two suggestions.
1.use the outputted ground points to construct DEM with some professional softwares, such as surfer.
2.apply low-pass filter to cloth mesh may help.
Looking forward for better solutions from all.