Description of terms within file format

[skinkie]

As developer/user I am currently reviewing the .sfm fileformat. I want to know what for example an intrinsicId is. OpenMVG is obviously a good place to start https://readthedocs.org/projects/openmvg/

[natowi]

Yes, I have some notes on the sfm format.

intrinsicId is used for images that share the same camera intrinsics.

Related and needs to be added to the docs, too:
alicevision/Meshroom#683

and

https://gist.github.com/natowi/ad9ce6d9f912e089bba9b69ec91d7115

[skinkie]

I was very surprised to see 2 intriniscs from the same smartphone camera. But I think this is the difference between focus macro vs infinity.

[natowi]

Yes. We can not use the same camera intrinsics for a different focus

[simogasp]

More generally, the sfm file is a mapping of the SfmData structure into a json format, normally the same name for the fields is preserved
https://github.com/alicevision/AliceVision/blob/develop/src/aliceVision/sfmData/SfMData.hpp
https://github.com/alicevision/AliceVision/blob/develop/src/aliceVision/sfmData/View.hpp