Exporting georeferenced mesh

[leo]

Hi Daniel,
I have one question. In order to give you some background I will write what I do and what I want to obtain. I have a georeferenced and classified point cloud according to vegetation/ground, now I want to calculate the total surface occupied by vegetation. In order to do that, I firstly divided the point cloud in 2 entities with scalar field/filter by value according to classification, then I created a mesh only for my vegetation point cloud. I then filtered the mesh with display params and then when satisfied by the results again filtered by values the mesh. Once I had the mesh ready I wanted to import it in another software in order to calculate the obtained fragmented surface. I exported both in .obj and .ply, both with binary and ascii but the ending result is that softwares like photoscan and meshlab don't read it or the ending result is made by stripes and rectangles as in the picture. I guess the problem is the cartographic coordinates. I did some tests exporting a different and less complex mesh project from photoscan to meshlab and I had similar issues until I chose to export with a local coordinate system. Do you have any suggestions?
Thank you, your help is always appreciated and fundamental.

[daniel]

The OBJ format doesn't necessarily handle large coordinates well. But the PLY format should. Anyway Meshlab doesn't handle large coordinates well.

I you want to compute the surface:
1) you can do it in CloudCompare
2) you can remove the 'Global Shift' information (Edit > Edit Global Shift & Scale) so as to export the mesh in a local coordinate system

[leo]

Thank you for the reply!
I will share how I resolved the issue, it is a bit different than what you suggested. I guess I missed something. But anyway:
-when one first opens a point cloud or a mesh with cartographic coordinates the global shift/scale box dialogue appears. There you can choose to preserve global shift on save or not (picture 1). On: will export the file with original coordinates; off: will export the file with a global shift.
- when you click edit global shift and scale on an already opened point cloud, it does not change if you click "keep original position fixed". The resulting saved file will keep the original coordinates anyway (picture 2)
In order to export the mesh with cloudcompare global shift written on the file I first saved the opened mesh I was working with, then opened back and unselected the "preserve global shift on save" box. Then save again. This way I succeeded. I don't know if this is the fastest way but it works.
About surface calculation, the final area done with CC is practically the same than the one calculated by meshlab.

[daniel]

Oh, when you open the 'Edit Global Shift' dialog, you simply have to set the 3 components to 0.

But your method works as well (it's just slightly longer).