Modeling Morphing Heads in Maya

 
 
 







This is not the only approach for modeling a polygonal head in Maya. Some people like to start with a cube or a sphere and edit it from there. This approach just happens to start with a polygonal outline that is extruded to make a head. However, most of the principles could be used for other approaches as well. This particular approach is to model a half head, which can then be mirrored to create a whole head. The important steps here are how you prepare your morph targets.
 

Using an extrusion method to make  a morphing head.

The first step is to use the "create polygon" tool to make an outline face that will be the base of your head shape.

It's best to start with something fairly simple, as you can always add detail later.

The next step is to select the face and extrude to start building your head shape.

At this point it's probably wise to start worrying about your mouth shape, as this is the probably the toughest part of the modeling process. There are a number of different methods for creating a mouth shape, so choose the one that's most comfortable for you. If you haven't built morphing, talking 3d heads before you may want to experiment a little.





Now you want to creat the rest of the facial detail. In this case, it's the eye sockets, ears and teeth.





Now it's time to mirror, reflect across and axis, etc... to turn your half head into a full head. Refer to the maya docs (Using Maya Modeling - pg. 593 - "Doing a Negative Scaling") for instructions on how to mirror a half head into a whole head.

In essence, the steps are:

  - extrude faces (together)
  - scale x -1
  - move into position
  - delete ridge of segments along middle of head

IMPORTANT NOTE: What they don't tell you in the Maya documentation is that if you don't remove the original outline face you created... then bad things will happen. So make sure your half head is hollow like the one below before doing the "negative scaling" operation as described in the Maya documentation. (just select the outline face and delete it)
 
 





Making your morph targets.

In order to make your morph targets you need to first make a number of copies of your finished head shape, and then modify each of these to be a particular head shape (mouth_open, eyes_shut, etc...).

Making a "blendshape" node.

To combine all your different morph models into a morphing head you need to shift-select them all, making sure that your home target (your home target needs to have the mouth closed and represent your characters most neutral expression) is selected last, which is indicated by the green hilight color.

Now go to the animations>deformations>blendshape option to create your morphing head. After this is done, you can select just the blendshape (your home target) and hide everything else in the scene, as the morph information is now embedded into your home model.

Checking your morphs. It's easy to check your morphs by going to the windows>animation editors>blendshape menu item and pulling up the blendshape dialogue box, which should look something like this.





Try dragging the sliders around and you'll see your head morphing.
 

Smoothing your morphing head.

All you have to do to make your head a high res morphing head is to select it and go to the polygons>smooth option. Then, you should see something more like this:
 
 





Adding material assignments. If you're not planning on using a texture on your head, you may want to assign different materials to different parts of the head, as in the image below.

To apply different materials to different parts of the head model, simply select the faces you want to assign your material to, select the material in the multi-lister and choose "assign" from the list on the popup menu (right mouse button)
 

                





Continue in this manner until you have applied all your materials to their respective groups of faces.

Once you've assigned materials it's time to add eyes and any other facial details that you may not have included in the head model. In this case the character needed eyebrows and a nose. 

 

Despite the limited amount of morph targets, the character is still capable of fairly expressive animation. To see a sample of this character in action, watch "The Dead Turtle Races" below.

The Dead Turtle Races

NOTE: After importing the character models into a template the animation above was completed from start to finish in less than two hours, using a realtime animation system with midi sliders.



A note on textures

If you're planning on using texture maps on a morphing head (and you want them to actually animate with your morph targets) then you'll need to make sure your model has uv coordinates in it. When you smooth an object it loses all texture coordinates, so you need to reapply them, and here are the steps:

- in facets mode select all faces of your object
- polygons>texture> cylindrical mapping

This will embed uv coordinates in the model, so that it will retain texture assignments and animate the texture along with the morf targets.