Some of AutoCAD commands that deal with solid modeling reveal a hidden option called RESFIT. For example, enter an invalid response to the Fillet command:
Select an edge or [Chain/Radius]: asdf
Expects a point or Edge/Chain/Radius/RESFIT
Select an edge or [Chain/Radius]: resfit
Resfit is short for "resolution fit." ACIS uses it as the fit tolerance value when approximating curves and surfaces.