Using Blend Shape for Facial Expressions

 

My name is Larry Neuberger and I am a professor at Alfred State College in Alfred NY. I created these handouts to use in my classes and most of my students found them to be helpful. I now decided to submit them to be published on the web hoping they can help others as well.

 

In this file we will go over using blend shape for facial expressions. This is an extremely easy and effective way to enhance you animations.

 

First we want to duplicate the mouse once for each expression or partial expression you want. (Fig. 1.) This depends on how much you want to control the face. You can have a head sculpted for individual expressions (I.E. happy, sad, angry, etc.), or you could have a duplicated head for individual body parts, which you can combine for more detailed expressions (I.E. raised eye brow, smile, from, grin, lowered brow, etc.). For this example I will simply sculpt a few individual body part expressions. Two for the eyes (open and squint) and two for the mouth (open and smile), which I can combine to get different facial expressions.

 

Fig. 1.

 

Next we want to sculpt each of the duplicated mice to the expression you want to present. (Fig. 2.)

 

Fig. 2.

 

Now that the duplicated mice are sculpted I can start my blend shapes. Select one duplicate geometry (in my case one of the duplicate mice) and then shift click the original to select it as well. I found it is longer to do it this way, but you have less complications doing blend shape one at a time. Then simply go to Deform > create Blend Shape . (Fig. 3.) When the option box opens up make sure you name it and have it set to local (Fig. 4.)

 

         

Fig. 3.                                                        Fig. 4.

 

Then to see your controllers and test the blend shape, go to Window > Animation Editors > Blend Shape. (Fig. 5.)

 

Fig. 5.

 

 

Now we can test our blend shape by dragging the slide bar up and down. (Fig 6 –7.)

 

         

Notice in Fig. 6 that the slide bar is set to 0 and the face is normal.
 
                       Fig. 6                                                            Fig. 7

 

 

Now in Fig. 7, the slide bar is up at 1 and the eyes are squinted, mouth closed, and I have an angry look.
 
 

 

 

 

 

 


Now to finish the last of the blend shapes simply repeat the steps listed above piece-by-piece and you will then have different expressions listed in the blend shape window where you can control and keyframe each. (Fig. 8.)

 

Fig. 8.

 

 

Observe below the different expressions that can be created with just four simple expressions created being controlled by the blend shape window. Each image shows one expression by itself. (Fig. 9 - 11.)

 

         

Fig. 9.                                                       Fig. 10.

 

Fig. 11.

 

 

Another way to get effective blend shapes is to do each component individually. For instance, if you did and eye squint and eye open for each eye individually, you would be able to have one eye squinting while the other is open wider. As with everything else in Maya, there are different ways to use each tool. The more you put into blend shape the greater the facial expressions you can achieve.

 

By doing blend shapes this way, in order to animate them you would have to use the blend shape window and make all your changes and setting keyframes there. This could be a huge pain and by spending a few more minutes, you can make animating these expressions easier.

 

What I plan to do is add attributes to the character which will be listed in the channel box. By doing this we could animate right there in the channel box with no unnecessary windows.

 

Select your character and go to modify > add attribute. (Fig 12.)

 

Fig. 12.

 

When the window opens, name your attribute, leave type to float, and set the minimum, maximum, and default values. I usually use o and 10, but that is personal opinion. You can use whatever numbers you feel comfortable with.

 

Fig. 13.

 

Once everything is named, click add, then ok and you will see your attributes listedin the channel box.

 

Now, all we have done is added the attributes. Now we have to make them work. This is where the set driven key tool comes in handy.

 

Go to animate > set driven key > set □, and open the blend shape window. These are the only wiondows you will need for this. Don’t worry if you can’t see you character. Once in the window, set it up as follows. (Fig. 14.)

 

 

 

  1. Choose your character and select load driver. You will now see the attributes you added. These will control your deformations.
  2. Now, in your blend shape window, press the select button next to the blend shape you are working with to select it. Then choose load driven. This is what will change.
  3. In the set driven key window, press key.
  4. Now, click on the attribute in the set driven key window to select it. Then in the channel box, change the attribute’s number to the max. value you set before.
  5. Then in the blend shape window, drag the slide bar for the blend shape you are working with up to 1.
  6. Then back in the set driven key window press key.

 
 

    Fig. 14.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

If that seems confusing hopefully this will help.

 

The attribute you set for your character will now control the deformations, so it will be the driver.

 

The blend shape’s we created before control the deformations now so they will be the driven.

 

By doing this, whenever you change the value of the driver (new attributes), the driven (blend shapes) will be affected.

 

Remember, when working in the set driven key window, the driver controls the actions driven. Similar to a car being driven by someone (a driver). The driver of the car controls the motion of it.

 

After that, simply repeat for each attribute individually. Now whenever you want to set a keyframe for it, simply select the character, change the value, and press “S” on the keyboard. Or if this is too complex for you, you can do all the animation through the blend shape window. I just wanted to give you some options.