Different resolutions due to number of digits

[Sebastian99]

Dear all,

I’m experiencing some trouble concerning the displayed resolution in CloudCompare. We are currently trying to record a point-cloud with RGB information and combine them with thermal images. Therefore we are recording a thermal panorama picture and put it on the point cloud instead of the RGB information, which get recorded automatically from the FARO Focus 3D.
For this purpose we load the point-cloud in Trimble RealWorks and substitute the RGB with the thermal panorama, which is working fine. I would also use another software but we could not find any which is capable to substitute or add other panorama Images on a point-cloud.
When I extract the point-cloud from Trimble RealWorks as an ascii-file and load it in CloudCompare, I’m witnessing an issue (or maybe I’m just not experienced enough to handle the software).

When I extract the point-cloud with 2 digits after the point (e.g. 7.16) then the displayed resolution is really low in CloudCompare. When I extract the same point-cloud with 5 digits (e.g. 7.15910) then the displayed resolution is way better (please see attached files).

The number of points in the clouds are not changing, it is really only the decimal place.

Greetings Sebastian

[daniel]

Of course, if you only have 2 digits per point you'll lose a lot of accuracy. The number of points doesn't change, it's only that several points end with the same coordinates after this trimming of information.

If the units of the cloud are 'meters', then keeping only 2 digits means that you keep only 'centimeters' and ignore everything smaller. Which means that all the points falling inside a centimeter cube will have the same coordinates... This is why you observe a kind of 'gridded' pattern.