Some common problems people may run into when using drivers.

Scripted Expression


A security warning in the Drivers panel.


An Auto-run warning in the Info editor's header.

By default Blender will restrict execution of Python scripts.

If using a Scripted Expression Driver Type that doesn't follow the Simple Expressions subset, you will have to open the file as Trusted Source, or set Auto Run Python Scripts in Preferences ‣ Save & Load ‣ Blender Files.


The Trusted Source checkbox in the File Browser.


The Auto Run Python Scripts checkbox in the Preferences.

Rotational Properties are Radians

Parts of the User Interface may use different units of measurements for angles, rotation. In the Graph Editor, while working with Drivers, all angles are Radians.