Remove undesired set of points from a pointcloud

[VictorGimenez]

Hello,

I asked this same doubt in another community but I didn't any reply yet, I am trying to remove a undesired set of points in the point cloud to remove objects which I don't want that be included in the file, for example, consider these point clouds below:

In the first one I am trying to remove these objects located at the left and right side of the legs and in the second one remove this base (turntable), how could I do it with MeshLab and after through python code? I have tried using Open3D https://www.open3d.org/docs/release/tutorial/geometry/pointcloud.html#Crop-point-cloud but this .json is being hard to understand.