Normals in laz export

[GGR]

Hello there,

I'm pretty interested in exploiting normals calculted in AM for future analysis, such as ground segmentation, with PDAL.

As far as I know, laz spec are not designed to embed normals data. But it is possible to export those from AM point cloud interface.

Because I can't find where and how are they stored, does anyone can help me on this ?

Cheers

[jochemla]

Hi there,
Normals are stored by Agisoft Metashape within LAS files as extra dimensions or extra bytes (you can use Lastools\lasinfo to see these fields), with field names being

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"normal x", "normal y", "normal z" with spaces without quotes
The convention (see this thread) for storing normals within LAS as established by ASPRS is instead to use the

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NormalX, NormalY, NormalZ
PDAL understands NormalX, nx or normal_x, but not that used by current Metashape exported las, "normal "x" with a space.

It would be great if Metashape could resolve that and use the official LAS normals naming convention instead on export - NormalX. Maybe this could be moved as a bugfix request.

Hope this helps.
Jonathan

[GGR]

Thank you Jochemla for this answer!

Indeed, a simple space can have a lot of impact! A colleague had put me on this path at the beginning of the week.

I totally agree with your proposal for bug reports. I'll post one that will point to this thread.

[Alexey Pasumansky]

Hello all,

In Metashape 2.0.3 we will add support for the normals for imported point clouds from NormalX, etc. tags.

But changes for the export format are not planned, as we expect PDAL to support Metashape-exported results:
https://github.com/ASPRSorg/LAS/issues/37#issuecomment-1710074402