  Complex animated transitions may be easier to understand when divided into
separate, consecutive stages. However, effective staging requires careful
attention to both animation semantics and timing parameters. We present
Gemini2, a system for creating staged animations from a sequence of chart
keyframes. Given only a start state and an end state, Gemini2 can automatically
recommend intermediate keyframes for designers to consider. The Gemini2
recommendation engine leverages Gemini, our prior work, and GraphScape to
itemize the given complex change into semantic edit operations and to recombine
operations into stages with a guided order for clearly conveying the semantics.
To evaluate Gemini2's recommendations, we conducted a human-subject study in
which participants ranked recommended animations from both Gemini2 and Gemini.
We find that Gemini2's animation recommendation ranking is well aligned with
subjects' preferences, and Gemini2 can recommend favorable animations that
Gemini cannot support.
