Global Registration open3D

[robertoruizmu]

I´m trying this global registration tutorial http://www.open3d.org/docs/release/tutorial/pipelines/global_registration.html?highlight=ransac#fast-global-registration , but I don´t know what values should I use for parameters like distance threshold in ICP registration and RANSAC, also in voxel size or CorrespondenceCheckerBasedOnEdgeLength. I mean, what kind of measure is it ? mm, cm, m? do they depend on the point cloud? What is a high or low value ? How can I set the correct value? I used the values in the tutorial, and changed them, but I can´t get a good aligment.
Thanks everyone !

[theNded]

voxel_size is in meter. The recommended value is 0.05 for a coarse scale and 0.0125 for a fine scale.
CorrespondenceCheckerBasedOnEdgeLength is a relative measurement, so metric doesn't matter.
RANSAC is really sensitive to data, as it is based on feature correspondences. Unfortunately there is no recommended setup that rules all data as of today.

[robertoruizmu]

thank you !

[germanros1987]

Please, @robertoruizmu consider marking this discussion as answered.