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Hello,

my issue concerns an inconsistency that I find between the eTibia Coordinate System (Left Implant) described in the PDF files with the same name, and the following sentence, found in the README.txt inside Geometry Data folder of the 5th dataset: "Note that the coordinate system (i.e., origin and axis directions) for the tray geometry is the consistent with the coordinate system for the eTibia load measurements".

But if we look at the coordinate system of e.g. "tibial Tray.stl" we clearly see that they are not consistent, as the {x, y, z} axes within the STL file correspond to {y, -z, -x} in the PDF.

So my question is: which is the right coordinate system?

Thanks in advance,

Marco

Hi Marco,

Sorry for the confusion. The error lies in the README.txt file. The file should state, "Note that the coordinate system (i.e., origin and axis directions) for the tray geometry is NOT consistent with the coordinate system for the eTibia load measurements". The origins of the two coordinate systems are located in the same place (center of the stem and on the surface of the tray). However, as you noted, the axes are not oriented in the same directions. I have corrected the README.txt file.

The coordinate system for the eTibia load measurements in the eTibia Data folders is defined consistent with the eTibia Coordinate System.pdf file.

Again, I apologize for the confusion and thanks for pointing it out!

Allison

Dear Allison,

again, thank you very much for your prompt reply, now it's perfectly clear.

Marco