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I am struggling to understand Meshlab's and 3D mesh file's relationships to georeferencing. I am coming from a GIS background, so I believe my assumptions on how this should work are preventing me from succeeding with 3D software.

I've found plenty of good tutorials for georeferencing in Meshlab online, but I haven't found one that discusses exporting the mesh with embedded coordinates to move to another software package with the benefit of the georeferencing.

I have an OBJ file of an archaeological site that I generated using photogrammetry software that is not georeferenced. I am using a text file of coordinates and the georeferencing dialog in Meshlab to georeference the mesh using the "pick a point on moving" method. This generally works great. And when I save the project and reopen it the mesh displays as georeferenced.

However, my expectation based on the way GIS works and based on how I figure scaled models should be exchangeable between software suites is that there is some way to write the georeferencing information to the mesh itself (rather than saved in the Meshlab project file).

I've exported the georeferenced mesh as OBJ and PLY but when importing into a new Meshlab project the model is no longer georeferenced. I've tried simplifying the coordinates (removing the leading digits on the UTM coordinates to emulate a smaller scale coordinate system) that I read can help if the coordinates are larger than the software is anticipating. But this hasn't made a difference.

There are numerous reasons I would benefit from the mesh itself being georeferenced. For example loading multiple georeferenced models into Meshlab at a later date to view their relationships, upload a georeferenced model to SketchFab so that is is properly scaled, and to create a stand alone scaled deliverable for a client or colleague that may use different 3D software.

Is there a separate command from "Export" to write this information to the mesh?

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The answer appears to be to use a filter to apply the transformation to the vertices of the mesh.

Filters > Mesh Layer > Matrix: Freeze Current Matrix

as discussed briefly here:

https://sourceforge.net/p/meshlab/discussion/499533/thread/e37c0c0d/

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