Remove the need for manual Manhattan alignmentm, use COLMAP instead

[danie1ll]

from COLMAP documentation:

COLMAP has functionality to align the coordinate axes of a reconstruction using a Manhattan world assumption, i.e. COLMAP can automatically determine the gravity axis and the major horizontal axis of the Manhattan world through vanishing point detection in the images. Please, refer to the model_orientation_aligner for more details.

https://github.com/talshilo/colmap/blob/master/doc/faq.rst

[kangpeilun]

Thank you. I tried Manhattan alignment using colmap before, but it was z-vertical instead of y-vertical as in the paper. I am not very familiar with the use of colmap, and I do not know whether the use of colmap can achieve the alignment effect in the paper.