Ray Ground filter not removing all the points on slopes

[jfqureshi]

Hello,

I am using Carla+ROS+Autoware.Ai to simulate an autonomous vehicle. I have been using Ray ground filter for ground removal from Lidar point cloud. But some of the ground points are not removed. On plane road surfaces, the filter works well. But on slopes(downhill), it doesn't remove all the points. It worked after I configured the filter based on this (https://github.com/autowarefoundation/autoware/issues/2863) discussion. But now I am having problems on slopes.

Here is the picture:
https://drive.google.com/file/d/1wFjWVSuTavSbPUBJVRmzNiumwkU7ZHNd/view?usp=sharing

In red are the /points_no_ground and in blue are the /points_raw.

Could anyone tell me how should I configure the filter better in order to remove the left out points?
I have tried to tune the parameters of the filter such as clipping_height, local_max_slope, etc. But still I don't have a very accurate removal.

Also, is there any way by which i can remove all the points from the PoinCloud which are below a height(let's say base_link)?

Any help would be appreciated.
Thanks