You could e.g. use the NeighborFinder with a 0.50 cm tolerance, where the red lines would be the Base and the other objects would be the Candidate. The features exiting UnmatchedCandidate would be the ones you're looking for.

Hi David, thank you for your answer, I tried the command you mentioned but the result is not good. I want to find objects that are not 0.5cm above the line. These objects are on average 4 meters away from the line. As a rule, I use the line as a reference and give the height 0.5 cm above. Since I'm doing this manually I may have measured incorrectly, so I'm looking for ones that are within 4 meters of the line and whose height is not 0.5 from the top of the line.

For example, the pink object here does not comply with the 0.50 rule.

Note that the NeighborFinder tolerance is base on the the ground units of the coordinate system of your data. So if the data is not projected in meters or centimeters, you may have to do that first.

Also, if you're working with PointClouds, you may need to use something else than the NeighborFinder.

I'm not using a point cloud right now, I have vector line data, I reference it from the middle of the rail and offset the object 0.5 above the line as a reference.