CloudCompare forum

I did scan dental cast with 3shape dental scanner, then I scanned dental impression with the same scanner, I think the scanner measures the scan in microns, then I did C2m analysis so the output should be in microns yes?

and how can I compare specific tooth or area in the cast? how can I get specific measurements for these areas

Yes, distances are expressed in the same units as the entities.

And you can use the 'scissors' tool or the 'Cross section' tool to segment parts of the meshes you want to compare.

C2m tool just measure the distance of the vertices from the refrance model
Or does it also measure the rms error

If you want to compute the RMS, select the cloud with the distance scalar field active, and use the 'Edit > Scalar fields > Show histogram' tool.

You'll see the RMS appear in the Console (it's automatically computed each time this tool is run)

So C2m measure what exactly ? The actual distance between 2 meshes ?

Nope, the distances from each point of the compared cloud to the nearest triangle of the reference mesh (one distance per compared point).

So from vertics to vertica. Or point of the triangle to point of the triangle
And the mean and sd that appear under the picture is the mean of all of these distance ? Yes ?

Or just point to any area of the nearest triangle ?

Not to the nearest vertex, but really to the nearest point somewhere on the triangle.