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complex cloud 2 mesh
Posted: Tue Sep 19, 2017 12:34 pm
by kro_pa
Hello,
How to do mesh from *.las - big and complex point cloud? Poincloud is from cave - very complex wall's relief, c.a 80 mln points.
1) Cloud have normals (by triangulation), 2) PSR on lv 8 split cave for different parts (screen in attch.), 3) PSR on on level 17 is a one big green buble :-), 4) PSR on higher levels was never made - reconstruction is always failed.
What do I wrong? Thanks for advice in advance.
Re: complex cloud 2 mesh
Posted: Thu Sep 21, 2017 6:27 pm
by daniel
Level 17 for PSR is already gigantic, so it's not a surprise that it fails above this level ;)
But the result is definitely not what I would have expected! Are the normals properly oriented? They seem to be a bit randomly oriented. How did you compute them exactly?
Re: complex cloud 2 mesh
Posted: Mon Sep 25, 2017 7:56 am
by kro_pa
Thank you for reply.
I have just made Edit/normals/compute. Then I've choose 'triangulation' , rest I have left as default.
Re: complex cloud 2 mesh
Posted: Tue Sep 26, 2017 5:57 pm
by daniel
Ah ok, then it's probably the cause of the issue here. Only computing the normals (with triangulation or any other algorithm) won't be sufficient. You need to get well oriented normals (i.e. all normals pointing outside of the surface for instance), which is generally not the case at first as CC can't guess where is the inside and where is the outside. You'll have to play with the 'Edit > Normals > Orient' methods, but it can be very tricky on complex shapes such as the share of your cloud. If you struggle too much, you can send me your cloud, and I'll give it a try.
Re: complex cloud 2 mesh
Posted: Tue Sep 26, 2017 8:34 pm
by kro_pa
Thank you. 'Orient normals' options are not active, they are grey... ?
Re: complex cloud 2 mesh
Posted: Tue Sep 26, 2017 9:38 pm
by daniel
Have you selected the cloud with normals?
Re: complex cloud 2 mesh
Posted: Wed Sep 27, 2017 9:33 am
by kro_pa
I did :-). After computing normals I have saved cloud as *.las again. Re-saving as *.las saves normals in cloud also or do I have to compute them again?
Re: complex cloud 2 mesh
Posted: Wed Sep 27, 2017 5:34 pm
by daniel
Sadly, LAS files don't store normals. You have to use either CloudCompare's BIN format, or the more generic PLY format.
Re: complex cloud 2 mesh
Posted: Tue Jun 04, 2019 6:06 pm
by paddywhells
I have a similar issue with a point cloud from within a cave. I'm having trouble orienting Normals effectively. I've tried Z, Barycenter, and spanning tree (knn=6) but get funky results. do you have any suggestions for a long narrow cave? Did a solution come out of this original post that I could use?
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Re: complex cloud 2 mesh
Posted: Thu Jun 06, 2019 7:25 pm
by daniel
Do you have a set of points describing the scanner path - in the middle of the cave / tunnels - maybe?