Dev:2.5/Source/Animation/Animato

Animato – An Improved Animation System for Blender

Joshua Leung
aligorith at gmail.com
January 2009

Blender’s Animation System has been showing its age and deficiencies recently, as the overall complexity and flexibility brought about during the last few years as a result of its Open-Sourcing, the growth spurts from developments necessary for the successful completion of the Open Movie projects (the ‘Orange’ and ‘Peach’ projects) and the Open Game project (‘Apricot’), have exceeded the simplistic system that was more than sufficient for an in-house software for NeoGeo back in 1994.

In addition to the increased stresses on the basic architecture – which were only made worse by the somewhat hackish implementation of the Action/NLA/Constraints systems based on the system used by Hash’s Animation:Master – the increasing complexity of Blender has led to a snowball effect in the complexity of features demanded by the user-base. The most notable of these, the “everything is animateable” idiom, was not feasible to be able to have in the old system, which was based on a set of fixed defines divided into ID-datablock and ‘fake’ datablock groupings. Although this system works quite well when there are only a few ‘static’ settings available (which were grouped directly in ID-datablocks), the inadequacies of such a system become apparent when the number of settings increases, and dynamic data (i.e. ID-Properties, Constraints, Modifiers, Nodes, and also Bones/Pose-Channels) becomes more widely used. 

Furthermore, there were some legacy hacks used to solve some specific production bottleneck at the time, which have been causing various usability issues. For instance, rotation curves (for objects) had their units divided by 10 in order to fit on the same axis scale as other animation curves, however, this resulted in many inconsistencies in the means for user interaction to occur. Another problem was the way that bitflag/boolean values (such as Object_Layers or Material_Mode) were exposed, with the raw shorts/ints that such values were stored in being directly exposed to the user, presenting a confusing interface for the animator. This was due to more of a technical limitation than a

The “Animato” system aims to rectify these issues, by addressing several of the main issues here in the following ways:

1. Data access is performed through the RNA (i.e. Data-API) system, which provides a method for accessing all user-editable settings in the same way as the UI and PyAPI allow, thus allowing “everything is animateable” (avoiding problems previous with accessing dynamic data). A number of benefits can be derived immediately from such a step, the details of which will be explored further in this document.
2. The complexity in the data layout of the old system is simplified through the introduction of a new container (AnimData) which gets stored in each major ID-block which can be animated, and the unification of IPO’s and Actions into a single type for the reuse of animation.
3. The evaluation code has been streamlined to reduce the need for various data to be calculated manually and multiple times by individual modules. Part of this stems from the decision to enforce strict separate of animation data from drivers, which allows rigs in a production environment to be more ‘animator proof’ and also more flexible.
4. Animation editors have been converted to use a data abstraction system, initially designed for use by the Action Editor only, which makes it easier to write tools which modify animation data (i.e. keyframes) without worrying about where the data comes from. This removes the restrictions regarding editing animation from multiple sources simultaneously, which was a serious limitation for animators working in older versions of Blender. In a framework where “everything is animateable”, it is certainly advanteous to be able to animate multiple settings at once.

Download WIP paper with graphics (.doc)