Change FCurve handles from Python

Question

I am currently trying to make an import script that generates an animation on a camera. The animation requires that the values for the left and right keyframe handles be set.

I couldn't find a way to set handle values explicitly, so I have tried to use bpy.ops.graph.select_border to select the keyframe handle that I want to set and then use bpy.ops.transform.translate to set it into place, however when I try to do this from my import operator, I get a RuntimeError saying context is incorrect

Does anyone know if the x and y handle values for an FCurve keyframe can be set from Python?

Answer 1

You will find it here:

action=bpy.data.actions['yourAction']
#or
action=bpy.data.objects['yourObject'].animation_data.action
#
action.fcurves[fcurve_index].keyframe_points[kf_index].left_handle
action.fcurves[fcurve_index].keyframe_points[kf_index].right_handle

You can easily explore blender's data structures with the outliner using the datablocks option and the interactive python console using autocompletion (Ctrl+Space).

If you hover over properties in the editor with python tooltips enabled it often will show you the path to the property.

Hint:

If the object has not been animated yet and thus animation_data is None, use the object's method animation_data_create to create it.

Afterwards assign an existing action to animation_data.action or create a new one:

action=bpy.data.actions.new('Your Name')

Note to the developers of blender:

In this case the path shown in the graph editor is abbreviated bpy.data.objects...left_handle and it is not possible to right click -> copy data path. So the hint shown is kind of useless.