17
Mar
09

Mighty Morphin’ Facial Expressions

Next up in our randomly appearing series of How Things Work, I thought that since it seems that one of the things Beyond the Tree tends to be noted for is how expressive the characters are, I’d give a fairly simplistic look on how they’re actually made. I use a technique called morphing, or morph targets – something I first found out about during a short course in 3ds Max I picked up during earlier studies. The Morpher modifier was essentially suggested to me for cases where bones are too complex or too unwieldy to make use of. While it certainly does have drawbacks – it’s not always as controllable as bones and when a model is turned, twisted and otherwise modified through bones and whatnot, morphs can sometimes behave unexpectedly. Blizzard, for example, uses bones to animate the expressions of their own characters in game.

So what are morphs? To use the lovely miss Te’len Nila to provide examples.. morph targets are copies of the original model that are then modified in a manner of your chosing; my defining these as morph targets, you pretty much get a sliding bar (per morph) that lets you slowly slide from one extreme to the other, with all the gradual steps inbetween automatically created for you. This is similar to image morphing, but with vertexes rather than pixels.

To show a straight down example, to the left we have the unmodified, blank expression of Te’len’s base model, and to the right we have the morph target for Te’len with her mouth fully open. The two stops inbetween show that with just the base expression and a single morph target, we can gradually slide between one and the other to have a wide slew of results automatically created for us.

The advantages with this is that we just need to create the morph targes and then use the sliders straight away with handy labels and all rather than having to understand a complex set of bones layered throughout the face just to make a character smile. The disadvantage is pretty much that you have to make a morph for every possible variation you want, which can amount to quite a few.

Starting with the eyes, this is essentially the morph target for every eye expression I use – here shown with both eyes at once, while I actually have seperate morph targets for each eyes so they can be adjusted accordingly. Do note, these don’t contain the morphs that just let the eyes look in different directions, but they essentially work on the same principle (and is something that still needs work, quite frankly). it’s interesting to note that some expressions can look slightly incomplete, somewhat over the top or the like – this is largely because some morphs (like, say, anger) is usually combined with others (anger tends to be paired with frown) to create a full effect.

The mouth is similar to eyes, though there’s no left and right side alternative (except for the mouth corner one). In hindsight, I noticed I forgot one of the morphs, pursed (essentially, making an o with your lips) which is used somewhat often, but it’s enough to get the idea across. It serves as an example though – pursed is something I didn’t have at first and then later worked into model revisions, along with the bite lip one. I find as I go along I tend to come up with new morphs I’m thinking might be useful and end up trying; some I keep, some I don’t. For example – bite lip was at first implemented as two seperate morphs: bite upper liip and bite lower lip – I ended up just keeping the latter because the former simply didn’t look good enough and I couldn’t find it useful enough.

So, combining all of this. With the above pictures as reference, it should be atleast somewhat possible to tell roughly what morphs are in use for what example. While I sometimes do wish I could do these things with bones due to the odd issue morphs sometimes have, morph targets have served as an integral part of how the model rigs I do work. The handy thing is also that they can do just about everything so long as you just move elements throughout the model topology (rather than add or remove anything), so it can be used for more than just the face; for example, one of the Hani Foonmall model revisions ended up with her having more in the terms of hips than I’d intended, so I actually made a morph for the sole purpose of reducing that.

Naturally, morph targets aren’t the end all solution to everything, and I tend to have a combined rig of both bones and morphs to fully articulate a model.. and like my usage of bones, the way I use and implement morphs gradually changes as I grow more proficient and come up with new and interesting ideas to try.

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5 Responses to “Mighty Morphin’ Facial Expressions”


  1. 1 Arafor
    March 18, 2009 at 07:24

    This is interesting, I was curious on how you did facial expressions. And she’s scary when pissed :3

  2. 2 Syndar the Grey
    March 18, 2009 at 19:49

    The 100% open mouth is creeeeeeeepy!!!!

    Anyway, Te’len’s face is the cutest in your story (and in the whole number of WoW webcomics I’m used to watch) so it’s great to see how you do it.

    Keep up the fantastic work!!!

  3. 3 Moltrazahn
    March 19, 2009 at 13:21

    ❤ i dont care how you make her look, she is still lovely!

    But the amount of options there is in this is quite interesting, i can see many great ways of utilising such “morphs”.

    As allways, im your humble fan.

  4. 4 BBR
    March 21, 2009 at 12:43

    Cool stuff.
    Tho i agree the 100% open is kinda creepy.

    Angry looks awesome 😛

  5. 5 Iasion
    March 26, 2009 at 21:31

    The 100% open mouth only looks strange because you don’t normally open your mouth that wide without some sort of expression in your eyes. If her eyes were wide open in that image then she’d look frightened, or if they were squinty you could imagine her trying to take a bite out of a big hamburger or something.


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