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Author Topic: PhotoMesh Layer Tiled Model Export Accuracy Issues  (Read 1772 times)

Kreshnik

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PhotoMesh Layer Tiled Model Export Accuracy Issues
« on: February 13, 2023, 07:53:34 PM »
Hello Agisoft Team,

the export of tiled models in the PhotoMesh Layer format seems to have huge accuracy issues which increase with the size of the reconstructed terrain.
We exported terrains with the size of >2km as tiled models and as textured models and overlayed them for comparison.
While the 2 reconstruction methods match perfectly inside of Metashape, the export of the tiled model as PhotoMesh Layer is very imprecise (I am talking about geospatial precission when measuring points in the projected coordinate system). The export of the textured modes is correct and exact and the coordinates match to the ones in Metashape.
The inaccuracys vary and can be >4m.
The accuracy issue is not a constant offset, but it seems to involve scale and rotation as well.
We assume that the transformed vertices in their respective coordinate system must create the issue on export of the PhotoMesh Layer format since inside of Metashape the coordinates are exact.
We are using Metashape version 2.0.0 (15597).

We wrote a 3-point alignment solution to align the tiled model data to the underlying textured model however even with this approach we still had bending issues and couldn't bring the precission down to what is required.