Remember that each sketch has its own internal coordinate system. Autodesk created a black-box algorithm to automatically create the sketch coordinate system. The internal x and y directions are NOT required to be consistent with the origin geometry. Instead the algorithm grabs convenient geometry that exists in the model and assigns a local +x and +y direction. I believe that the sketch x axis is the horizontal direction and the sketch y axis is the vertical direction. There is no chance for the user to control the sketch coordinate system at sketch creation.
It is possible to manually re-define the sketch coordinate system after sketch creation. It has to be done outside the sketch environment, and is easiest if done before any sketch geometry is created or projected. RMB on an existing sketch to get the Edit Coordinate System command. See the screenshot below.
If changes to previous features delete or alter the geometry that the sketch coordinate system algorithm picked, users need this command in complex models when edits/new features are added to the model tree before the sketch.

Steve Walton
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Inventor 2025
Vault Professional 2025