In this case, I did not register this dataset myself. In support of your question though, in order to not skew the results of your measurement surface, you would want to exclude whatever surface you are wanting to measure levelness/flatness of from the cloud-to-cloud constraints.
THis video gave me a great idea to solve a problem i was having, thanks for sharing!
Glad it helped!
Question, are you excluding the floor below each setup in your C2C registration and relying HDS targets and C2C of ceiling / wall features?
In this case, I did not register this dataset myself. In support of your question though, in order to not skew the results of your measurement surface, you would want to exclude whatever surface you are wanting to measure levelness/flatness of from the cloud-to-cloud constraints.