This is a protractor for measuring corners. For instance it can be used to determine the angle between two walls. It has the advantage of being able to push up against two flat surfaces as opposed to a regular protractor that is more of a 2 dimensional approach to measuring angles.
To complete the protractor, you will need two main arms one gauge arm, one cross arm and the protractor piece.
I designed the model in Solidworks. I printed the arm pieces with my Qidi tech with black ABS filament and I printed the protractor with the Anycubic Photon in order to have fine enough resolution to make out the numbers and graduations.
The author marked this model as their own original creation.