Cloud / Cloud distance

[laura]

Hi Daniel,

I want to compare two clouds to find the difference in the 3 directions, I am especially interested by x and y, so I compute cloud / cloud distance and I tick “split X, Y and Z components” but my results aren't relevant. I evaluate my difference in x and y to 2 or 3 meters max but I obtain a mean of -956 for absolute distances (X) and 1220 for (Y). And I also have many values equal to 0. Do you have any idea to correct this issue ?

Thanks !
Laura

[daniel]

1) are you sure your units are in meters and not in mm for instance?

2) the distance used is the 'closest point' distance by default. Therefore it is not necessarily in the direction you expect. To get more control you should consider using the M3C2 plugin

[laura]

Thank you for the quick reply !
I ran M3C2 plugin but I am not sure to understand the output file, is Nx my shift along x and Ny along y ?

[daniel]

Sorry, I was not very clear. M3C2 only gives you the ability to control in which direction the distances are computed (thanks to the normal, that you can constrain to be purely vertical, or in the horizontal plane, etc.). But you can't split the distances along each dimension for now (that would be a nice addition though).

[laura]

So I have another question, Can I find the displacement vector if I multiply the M3C2 distance with the normale ?

[daniel]

Yes, that's the idea.