Movements that went into Coraline's face was over 200,000

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Discussion Overview

The discussion revolves around the number of facial movement combinations used in the film Coraline, specifically addressing the claim of over 200,000 combinations. Participants explore the implications of this number in terms of permutations, the physical modeling of facial expressions, and the assumptions behind the calculations of movement points and positions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants question the interpretation of the 200,000 combinations, suggesting that not all permutations result in meaningful facial expressions.
  • There is a proposal that if each point of movement has 5 positions, it would require 8 points to exceed 200,000 permutations, although this is debated.
  • Concerns are raised about the assumption that the upper and lower halves of Coraline's face could be modeled separately without affecting the overall expression.
  • One participant suggests that a more careful distinction between positions and movements is necessary, proposing that around 450 different facial positions would be needed to achieve 200,000 movements.
  • A reference to a model with 68 parameters for facial animation is introduced, indicating a more complex approach to facial movements.

Areas of Agreement / Disagreement

Participants express differing views on the validity of the assumptions regarding facial modeling and the calculations of movement combinations. There is no consensus on the implications of the 200,000 combinations or the methodology used to arrive at that number.

Contextual Notes

Participants highlight limitations in their assumptions, such as the potential for non-meaningful combinations and the complexity of facial movements that may not be captured by simple models.

DaveC426913
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I heard on the news a tidbit about the film Coraline. They said the number of combinations of movements that went into Coraline's face was over 200,000.

They made that sound like it was a huge number and a lot of work. But of course, I know they're talking about permutations, which dramatically decreases the necessary number of inputs.

I was trying to figure out (while driving) how few points of motion it would require to exceed 200,000 permutations, but I got stuck.

Say each point of movement (an eyebrow, tip of the nose, corner of the mouth) has only 5 positions (way down, down, neutral, up, way up). How many points must there be?

It's not 200,000 = 5^n is it?

That makes a mere 8 points of movement required to make 200,000 expressions.
 
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DaveC426913 said:
Say each point of movement (an eyebrow, tip of the nose, corner of the mouth) has only 5 positions (way down, down, neutral, up, way up). How many points must there be?

It's not 200,000 = 5^n is it?

That makes a mere 8 points of movement required to make 200,000 expressions.

This would be the correct setup for your assumptions. But I don't think it's quite as easy as that because not every possible combination of positions makes a meaningful facial expression.
 


owlpride said:
But I don't think it's quite as easy as that because not every possible combination of positions makes a meaningful facial expression.
It doesn't have to be meaningful; they're simply trying to claim a big number for the radio.
 


Didn't they build physical models for the faces? Because in that case I doubt they would have built faces that don't correspond to meaningful expressions.
 


owlpride said:
Didn't they build physical models for the faces? Because in that case I doubt they would have built faces that don't correspond to meaningful expressions.
Perhaps, but I'll bet my paycheque they didn't build 200,000 physical models.
 


Assuming they built the upper and lower halves of her face separately, they would get by with 1,000 physical models for 200,000 combinations. Or maybe they only built the jaws and animated the rest?

Replacement Faces
 


owlpride said:
Assuming they built the upper and lower halves of her face separately, they would get by with 1,000 physical models for 200,000 combinations. Or maybe they only built the jaws and animated the rest?

Replacement Faces
Why is it a good assumption that they would bulld the upper and lower halves of the face separately? If they're going to the trouble of making 200,000 possible facial expressions, I doubt they'd take such a huge shortcut as to pretend (erroneously) that movements of the jaw and mouth have no effect on the contours of the upper face. Those subtleties are kind of the whole point of going to that much trouble.
 
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So, what is the answer? With my proposal of a (very moderate) upper limit of 5 positions per point, how many points would the face have to have 200,000 unique combinations?

Was I right that the answer is 8?

I guess it has to be. Not sure why it seemed so difficult before. I guess because I started with the premise that it was going to involve a factorial rather than a simple exponent.
 


DaveC426913 said:
Why is it a good assumption that they would bulld the upper and lower halves of the face separately? If they're going to the trouble of making 200,000 possible facial expressions, I dount they'd take such a huge shortcut as to pretend (erroneously) that movements of the jaw and mouth have no effect on the contours of the upper face. Those subtleties are knod of the whole point of going to that much trouble.

Did you look at the link I posted? It seems like a legitimate assumption because all pictures I have seen of Coraline faces only show half faces.
 
  • #10


owlpride said:
Did you look at the link I posted? It seems like a legitimate assumption because all pictures I have seen of Coraline faces only show half faces.
I see your point.
 
  • #11


DaveC426913 said:
I heard on the news a tidbit about the film Coraline. They said the number of combinations of movements that went into Coraline's face was over 200,000.

I just realized that we should be more careful about positions vs movements. If we have x positions, there are x*(x-1) possible movements between two (ordered) positions. We would need about 450 different facial positions to get a total of 200,000 movements.
 
  • #12


One of the commonly used extensive models of facial animation has 68 parameters:
http://www.dsp.dist.unige.it/~pok/RESEARCH/MPEG/fapspec.htm

The parameters are real values between some maximum and minimum values, so the parameter space is a 68 dimensional box.
 
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