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Author Topic: Camera.xml export with "proper" local coordinates -> NeRF opportunity!!!  (Read 3555 times)

3create

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As has been mentioned in a few forum discussions here, exporting the aligned cameras as XML results in strange transformations: Metashape uses it's local coordinate system with no obvious correlation/transformation matrix to the "real" coordniates. Only option is exporting as "omega phi kappa", but this lacks other information, such as camera intrinsics.

Both instant NGP and Nerfstudio have scripts for converting Metashape-camera.xml into their own format (transforms.json).  This resulting file however inherits the "arbitary" transformations of the original Metashape xml

Sure, Nerfs are still in an expiremental phase, but IMHO the future potential is obvious! Thus, the combination of the solid alignment from Metashape (with all the options in this phase, i.e. individual pre-calibration, masks, and and and) make it an ideal fit for Nerfs.

So PLEASE, adjust the XML export, so it obviously reflects the user-defined local coordinats! That would be such an opportunity!

3create

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I'd also like to add, that Reality Capture's camera export behaves just as one would expect, and the resulting NeRF is therfore in the correct orientation/scale (NeRFs then internally scale to a 0 -1 space, but this transformation is documented and can be correctly reverted for further steps).

And a another motivition I didn't mention in the OP: it's not only Metashape's alignment process that is of interest, but also its superior mesh reconstruction and texturing: with known transformations, the mesh can be used for pricise 3d/2d compostiing work with the NeRF renderings, rather than doing guess work with the Blender NeRF-plugin.