Ubuntu Linux 14.04 (64-bit)
NVIDIA GTX 960 (NVIDIA Driver Version 367.35)
Broken: 2.77a abf6f08
I've found that custom properties stored within PropertyGroups and/or CollectionPropertys cannot actually be animated if they are associated with a PoseBone (Error returned when inserting keyframe is "Failed to resolve path to property, try manually specifying this using a Keying Set instead"). (If the exact same custom properties are associated with an Object, they can be animated by inserting keyframes normally.)
It's possible that I'm mistaken and it is possible to manually specify the property within a CollectionProperty/PropertyGroup using a Keying Set in a more straightforward manner (or at all), but to manually add a Keying Set for every potential instance of a property within a CollectionProperty for every PoseBone that uses the custom properties is an unrealistic for any use case involving a CollectionProperty (and honestly I'm doubtful whether this is even possible, I was unable to successfully create a Keying Set for keyframing a property within a CollectionProperty/PropertyGroup, getting error 'Keying set failed to insert any key frames', although I can't deny the possibility I got the path to the property wrong somehow).
Exact steps for others to reproduce the error
- Open the provided .blend file
- Install/Enable the provided add-on
- Select a bone in the armature in pose mode.
- Go to the Bone panel. At the bottom, you'll see a new section called 'Custom Properties Bug'.
- Try to insert a keyframe for 'Animatable PropGroup Property'. It will fail.
- Click the 'Add Collection Item' button to add an item to a CollectionProperty.
- Try to insert a keyframe for 'Animatable Collection Property' (a property within the Item you just added to a collection associated with the PoseBone). It will fail.