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cornelmpop / Lithics3D

An R package for processing and analyzing 3D scans of archaeological lithics
GNU General Public License v2.0
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Discrepancy between output of edge_angles_yw and the Virtual Goniometer Meshlab plugin #20

Closed cornelmpop closed 9 months ago

cornelmpop commented 9 months ago

There is a major (18 degrees) difference in the outputs of the edge_angles_yw and Virtual Goniometer Meshlab plugin with the following inputs:

mesh <- Rvcg::vcgUpdateNormals(demoFlake2$mesh) res <- edge_angles_yw(mesh = mesh, poi = data.frame(x = c(16.395319), y = c(51.524971), z = c(409.201294)), radius = 2.994467, lambda = 2)

The angle computed above is 121.166, while the Meshlab plugin returns an angle of 139.2329.

cornelmpop commented 9 months ago

Since other POIs work fine (i.e., difference of less than 1 degree), and given the odd placement of this POI (an angle measurement at this location makes very little sense), this is most likely due to patch selection using Euclidean (Lithics3D) versus geodesic (Meshlab plugin) distances.

This is important to document, but unless it is shown that this is not a meaningless edge case, I will not dig any deeper.