The starting point of my work on the Face Editor was the creation of fixed "emotion" faces. These were individual expressions meant to show particular emotions such as anger, happiness, suspiciousness, etc.
I then added to that a system for animating faces involving what I call "excursions". A simple excursion might be "look down and to the right". The face would begin at a fixed emotion face and morph in a series of steps to the “down and to the right" expression, then morph back to the emotion face, like so:
Now I am considering three possible extensions to this:
1. Fractional expressions
This would entail the addition of a numeric parameter between 0.0 and 1.0. The expression would then be drawn at only that percentage of its difference with the null expression. This would permit degrees of intensity of expressions. Of course, we could always do this with specific expressions. However, we might be able to re-define all expressions in terms of just the three emotions/moods, using six expressions in total, one of each extreme of the emotion, with null always in the center position.
2. Variations
These would be small variations on the existing expressions. There could be, say, three different versions of the ‘angry’ expression, and the system could shift from one to the other.
3. Single-feature excursions
These would be added to the existing emotional expressions. Like so:
These possibilities are exciting, but before considering them further I must first come up with better nomenclature. There is already some confusion between the overall term expression and the two variations emotion and excursion. Moreover, these three new ideas might not need any new terminology. I shall sleep on it and return to the issue tomorrow.
Tomorrow
Well, actually, it’s today. The above was written yesterday. Well, you’re probably reading this much later. Time travel via the web!
I now realize that fractional expressions can be used in both directions. That is, we could start with the angry expression at full intensity, then back it off to, say, 90%, then ramp back up to 100%, then back down to 60%, and so on.
Superposed expressions
This would be an excursion that does not alter the existing emotion. Consider, for example, the first animation above. It completely loses the angry part of the expression while engaged. What if we could have an excursion that leaves the other features intact? For example, an angry expression could look to the right without changing the other features.
It would be especially nice if an excursion can be fully superposed over an emotion. For example, an angry emotion could still show the entire face looking to the right without changing its basic angry expression. But I don’t think that can be done.
Conclusions
I will add two new features to the Face Editor. The first is an additional parameter to the drawFace method that draws only a fraction of the emotion. The second is a boolean trait that applies to each feature in an excursion. The default value is true, but if set to false, that feature will not undergo any changes during the excursion.