c2c distance

[ahmed]

hello,
for check of c2c distance
i import points and apply transformation ( translation in x =1) y=0 , z=0 ,
and compared the original and translated clouds.
it must be = 1
but after apply c2c the mean = 0.45
?????
what is the problem?
i choosed all the scale = 1
thanks,

[daniel]

Warning, C2C distance is the distance to the nearest point.

So depending on your cloud shape it's not necessarily '1' after the translation. It would only be so for a plane and if the translation is applied normal to the plane.

[ahmed]

hello,
is it mean that,
c2c don't measure the change occured in point clouds??
if i want to measure the change occured in clouds, what software can used??
thanks for your answer,

[daniel]

The 'c2c distances' computation tool does detect changes between clouds... but not necessarily in the way you are expecting ;)

If you want to measure the movements in particular directions, then you should look at the M3C2 plugin (http://www.cloudcompare.org/doc/wiki/in ... 2_(plugin)). Of course this tool will ask you for more parameters as it's much more evovled ;)

[ahmed]

in M3C2, when i have point cloud of a building and after time scanned again to get the movement. by m3c2 can determine the movement between the 2 point clouds??
what main by scales (in main parameters) and normals
thanks for your answer.

[daniel]

For the right parameters you can use the 'guess params' button, but it's better to read the wiki documentation (and even better the M3C2 article) to clearly understand what you are doing. Especially for the normals orientation, as you seem to be interested in monitoring displacements in particular directions.