Pointcloud problem

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profesjonalc
Posts: 3
Joined: Thu Apr 14, 2022 12:45 pm

Pointcloud problem

Post by profesjonalc »

Hello

I have a problem with displaying certain pointclouds. When I import it (.las), it segmets the pointcloud in straight lines as shown in the pictures, when the points should be random as in 3rd image. Sometimes it happens after using segmentation tool and sometimes with raw import. Other programs open the same file nicely, as shown in the last picture. The biggest problem is, that if I export this pointcloud, it will be "with lines" as well.

This is a sample of powerline, zoomed in in CloudCompare and zoomed in in some other pointcloud program.


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daniel
Site Admin
Posts: 7382
Joined: Wed Oct 13, 2010 7:34 am
Location: Grenoble, France
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Re: Pointcloud problem

Post by daniel »

Yep, that's the very classical issue with large coordinates.

Make sure you apply a Global Shift when prompted by CloudCompare at loading time. And make sure also that the Global Shift is sufficient to reduce the temporary local coordinates to something small, so that the numerical accuracy is not lost.

D'ont hesitate to read the explanation provided by the dialog (the 'question mark' button at the top right). And also consider that this shift is only temporary and the original coordinates will be restored at export time.
Daniel, CloudCompare admin
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