CloudCompare forum

Hi,
I am new to CC, I am comparing the laser scanning point cloud and photogrammetric point cloud, and i computed the M3C2 distance between two point cloud, and it show the mean and standard deviation after i plot the Guass distribution fitting, but i didn't find any other information such as rms, sigma.
Do i need to export it to excel and do it by myself? is there any other assessments recommend to do, i am also trying to export the m3c2 point cloud to compute the rms of distance uncertainty.

If you really fit a Gaussian Distribution to the histogram, then you should also get the RMS in the Console (with the latest versions). And the 'sigma' is the standard deviation ;).

Otherwise you can indeed export all the points and their associated scalar fields (distance, confidence, etc.) by select the resulting cloud and saving it as an 'ASCII/text' file. You can even set the separator to 'comma' to get a nice CSV file that you can open in Excel (assuming there's not too many points ;).

Thanks for the quick reply!
But you mention about exporting the confidence, when I exported the result point cloud I didn’t find the column about the confidence, the point cloud I exported only have these parameters including point coordinates (x, y, z), significant change, distance uncertainty, m3c2 distance and also the normals(x,y,z). Where should I look for the confidence?

Sorry, confidence and uncertainty is almost the same in my mind ;)

i think i still have a dumb question to ask, before i computed the cloud to cloud distance between two point clouds (photogrammtry point cloud and laser scanning point cloud), my photogrammetric point cloud was already scaled based on the survey points from laser scanning data from other software, do i still need to run fine registration? or i just directly compute the cloud to cloud distance?

If it's only scaled, then you'd better run the registration first yes. But if it's already scaled AND registered, then no need to use fine registration of course.