Get camera FCurve

Question

object.animation_data.action.fcurves

Always works on any object, but if try it on a camera

Python: Traceback (most recent call last): File "C:\Users\korb\AppData\Roaming\Blender Foundation\Blender\2.93\scripts\addons\plugin_init_.py", line 155, in execute cf = camera.animation_data.action.fcurves AttributeError: 'NoneType' object has no attribute 'action'

Answer 1

To debug your problem, look closely at this part of the error message:

in execute cf = camera.animation_data.action.fcurves AttributeError: 'NoneType' object has no attribute 'action'

NoneType is telling you that one of the attributes of camera.animation_data.action.fcurves has no value and so it can't have an attribute.

action is telling you where Python had to stop parsing the variable. The attribute before action is animation_data. This tells you that camera has an empty animation_data attribute.

You confirmed this by running the suggested test:

if camera.animation_data is None: print('oops')

on the Python console. It printed "oops" verifying that the value of camera.animation_data was empty.

It turned out that the reason for this is because you had set camera incorrectly, perhaps by setting it to bpy.context.scene.camera or bpy.data.objects["Camera"]. That's because when you animated the focal length, (the variable is lens, by the way) The animation data was actually attached to bpy.data.cameras["Camera"].

So that means that the reference you need is bpy.data.cameras["Camera"].animation_data.action.fcurves.

This of course, is only true if there is only one camera and you haven't changed its name to something other than "Camera". In other cases, you'd have to find a different way to select the correct camera from bpy.data.cameras.