Character Animation with 3DSMAX [10 mn de lecture - paru le 9/9/2004 11:15:25 AM - Public : Confirmé]

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Maxence MAMY Elève-Ingénieur Supinfo Paris Promotion SUPINFO 2004    Lui écrire    Tous les projets de cet auteur    Le mini-CV de cet auteur

7. Facial animation

Now, that you know how to animate your characters's body, we're going to see how to animate their face, to give them expressions and even to make them speak.

It is important to identify the main lines of the face which can mark the expressions: eyes and eyebrows, as well as those who are going to produce phonemes : the mouth and the jaw.

We shall use the Morph modifier for the animation. It do a morphing between several target objects (Be carrefull : the target objects necessarily must have the same number of vertex).

7.1. Preparation

Load a file containing a character or a head. Select the mesh, go in the Selection Modifiers and choose Mesh Select.

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Select the components points of the lower lip

In the Animation Modifiers, choose LinkXForm. This modifiers is able to link a part or the entire mesh to a control object. All modifications done on this control object shall be affected on selected part of the mesh.

Then, in the Free Form Deformers, choose a FDD Box. This modifiers is a box with an adjustable number of points, containing the mesh selection allowing to do transformations with a restricted number of points.

Repeat the operation for all parts of the face you will deform.

The upper lip.

The eyes

The eyebrows

The jaw

Use the Soft Selection option which allow a gradation on the selection. Turn on the checkbox Edge Distance to make the gradation on contigues edges.

7.1.1. Expressions

Now comes the deformation phase of the face to give it expressions and phonemes. I advise you to take a mirror to analyze the deformations which undergoes your face (I you advice also to lock your door to avoid be taking for a madman).

The face give the expressions, there is a lot. We shall linger here only in the most meaning and the most common which will allow then in combining them to form the others.

Blinking : important to give life to a face

Eyebrows up : Finish sentences, surprise, interrogation..

Eyebrows frown : concentration, supports arguments

Anger : eyebrows down, Cheeks go up. It's a contraction of the zone eyes, cheeks, nose.

Sadness : the face is pulled down.

Smile : at the opposite of the sadness, the face is pulled up

Le laughter : Like the smile but with the mouth big opened.

7.1.2. Phonemes

Phoneme is the elementary sound of a language, the smallest sound unity. There are in the French language exactly 36 phonemes but it's not necessary to model  of them. It's possible to group them together by resemblance.

a  : Jaw big opened.

i, é, è : Jaw a little opened. Lips stretch in width, cheeks go up a little, like a smile.

o, e : jaw is little opened. cheeks are hollowed, mouth in an oval shape and lips are pushed in front.

f, v : Jaw is little bit opened, the under lip comes to stick to front teeths.

b, m, p : Lips are crushed together, jaw is a little bit opened.

u : The mouth is squeezed in an O shape with folds on lips, jaw is opened just a little.

7.1.3. Morpher

In the modifiers list, select Morph.

3DSMax can do a morphing between all the objects possessing the same number of vertex. The objects which are morphed in the other one are called morph targets.

In the morph roll out, it's possible to load targets one by one or to load several in one time. Click on Load Multiple Target.

Select all the morph targets.

You have now one target by slot. It's possible to deform the mesh by giving a value in percentage towards the target.

To create more expressions, i advice to combine several targets rather than to create other targets.

7.2. Animation

Now that all the targets are ready to use, you can animate.

Let's do in first the eyes, we are going to affect them a constraint so they'll follow an object of the look. Create a target camera, move the target on the face. Select then the 2 eyes, go into the animation panel, develop the Assign Controler roll out, select Rotation and click on  Assign Controler.

Choose LookAt Constraint.

Then in the LookAt Constraint roll out, select the camera as target.

Then if you have model teeths (or get some), it must follow the jaw movement.

In the Create panel, in Helpers, select Point and turn on the Box checkbox. Select the helper and go in the Animation panel, develop the Assign Controler roll out, select Position and click on Assign Controler.

Choose the Attachement constraint.

Select the head of your character as target. Click on Set Position and move the helper on the chin.

With the Link tool, link the lower teeths to the helper. Teeths 'll move with the jaw now.

Now we're going to make our character speak. For this, we need an audio file of a speaking person (this may be you). Then you need to analyse the sentence.

Example taken from the movie Finding Nemo in french : " .. de toi mon p'tit monsieur, affronter des méduses ... tu pratique de drôles de sport extrêmes coco ... incroyable ..."

It's necessary to place corresponding phonemes according to the sentence. So create keys for each phonemes according to the sound.

De	toi	m ...	...on
p...	...'tit	m...	...onsieur
a...	...ff...	...ron...	...ter
des	m...	...é...	...duses
tu	p...	...ra...	...tique
de	droles	de	sp...
...ort	ex...	...trêmes	coco
in...	...cro...	...ya...	...ble

For some "o", it's better to mix the "e" and the "u".

Then do a right click in any view and chooseCurve Editor.

Develop World a,d do a right click on Sound, choose Property.

Click on Choose Sound and load an audio file of a speaking person.

Here's the sound loaded in the scene. (If you push the play button in the animation bar, the sound is played in the same time).

Then, develop the tab of the mesh, to the Morpher modifier. For every Morph targets adjust keys and tangents of these by playing in loop the animation. There is no miracle method, it's necessary to analyze the way our face moves.

For example for a blinking of eye, adjust tangents to Fast.

When the animation of phonemes is well synchronized with the sound, add expressions. Raise eyebrows for the purposes of sentences, frown to argue, and make move the head. It is important to note that to give life to a character, it shouldn't be static, he has to be in perpetual movement.