Expert: Andre Hickman - 6/15/2008

Question
Hello there.  
Although I use Maya, I am sure you can still answer these quick questions.  I have been practicing modeling heads using a method on www.simply3dworld.com.  He models all of his heads with the mouths open.  Most other tutorials I see model the heads with the mouth either closed or barely open.  Which is better when I get ready to animate my head or does it make any difference?

Answer
Hey Vincent.  

I tried to go to simply3dworld.com, but something was wrong with there site...or my computer...lol. At any rate, although I can't see their modelling tutorial, I would explain it like this: he probably models with mouths open so he doesn't have confusing vertices when assigning them to the animation modifiers and rig.  

Think of it this way, if the mouth is closed, you will have a whole bunch of vertex in very close proximity to one another where the lips meet.  when trying to choose the right ones to assign to a modifier, or to manually animate, could become like picking out red M&M's in a bag of Skittles...sure it's possible, but it would take time and careful selection and focus to make sure each one was an M&M or a Skittle...and why the heck did you have M&M's in a bag of Skittles anyways?!  At any rate, with the mouth full open, the vertices are at the furthest distance away from each other as possible, and selection is very easy.  You wouldn't accidentally select a vertex from the bottom lip while trying to capture all of the top lip vertices, etc.  

Now the 'slightly opened' version is a compromise between the two.  you may have vertices close together, especially near the corners of the mouth, but this initial pose is a somewhat natural pose in facial expressions, and is a neutral pose.  When modelling with the mouth open wide, you may get an unexpected look when animating the mouth to close, and the lips may fall together unnaturally.

In summary, you want to separate the lips, but you want to do so in moderation so as to keep the facial model in a neutral pose, to get the best results.  I wouldn't ever start with the lips touching, because it will get confusing later, and I wouldn't make the mouth full open, unless it were like a cartoon character type model, and did not have to look realistic in the mouth area. other than that, stay in the neutral pose, with the lips slightly separated.

I hope this helps.

Cheers,
Andre'