This specification describes technologies that relate to creating animation effects in an animation at runtime and without requiring the animation effects to be stored in every frame or time instance of the animation. In general, one aspect of the subject matter described in this specification can be embodied in a method that includes obtaining animation information having a primary object and a first effect object associated with the primary object. The method also includes generating an animation sequence using the animation information. The animation sequence includes the primary object on which the first effect object and a second effect object can be applied. The act of generating an animation sequence includes interpolating between the first and second effect objects to create at least one intermediate effect applied to the primary object in the animation sequence. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products.