View Full Version : Help: Crease deformation while smiling
03 March 2006, 06:48 AM
Hi guys. When we smile there will be a crease deformation the end tip of our mouth and our cheeks. How can it be achieve in animation. I have the book "Stop Staring" by Jason Osipa. I reference the edgeloop from there.
What I couldnt understand is how can it apply in animation. Must i have a proper rigging + skinning to achieve the deformation? And what is the proper way to rig and skin that area?
Thanks guys ;)
03 March 2006, 11:42 AM
Thatīs is what itīs all about in organic deformation. Some people use muscle systems, some use blend shapes and Maya use cluster/wrap/wrinkle deformer.
I donīt know what 3D package you are using, so Iīll keep it on a general scale.
Create a duplicate of your mesh and add a facial rig with bones onto it that simulates the main facial muscles (for example the m.zygomaticus major). Use the bones to create the neccesary facial expressions. Freeze/bake the transformation onto the mesh, remodel the face with wrinkles, creases, muscle bulges and add it to your main rig as a morph/blendshape.
Thatīs facial expressions in a nutshell. Most proīs will have their own tricks and scipts to optimize the whole process.You can always use the rig directly, but to create wrinkles you will need advanced bones systems, where one bone pulls the skin inside and another the other bones keep the skin in place. There are lots of possibilities and each 3D package has its own tricks, so stay curious :)!
03 March 2006, 11:56 AM
Stylize, if you own the Osipa's book... just read what it says! Osipa's UI is based on morphers/blend shapes, so what you have to do is modelling the smile shape using poly tools (i guess you are working on polys), taking care in the crease areas.
As I say, just look at how he does it: it's fully explained there ;)
03 March 2006, 02:30 PM
Thanks for the fast response :)
Thanks for the tips. I'm using 3ds max for my current project. Too bad i cant use the morph/blendshape method. I can only use bones for the animation. Probably the one bone pulls the skin inside and another the other bones keep the skin in place method could work. Will have to do research and test on that. Thanks:)
I know that book is based on morphers/blend shapes. It really showed me the proper shapes of those areas. Too bad due to the constraints, i cant use that method. So i have to look into custom facial rig to achieve my goal :)
I will be glad to have anyone who can share with me their method in this area. Thanks. keep it comin:thumbsup:
03 March 2006, 02:38 PM
Max has Morphs as well! Take a look at the modifiers. I think you have to add the morph before the skin modifier, but it IS possible. I did my diploma project with that to create facial expressions. Do the skeleton approach to create template morphs, refine with soft selection and then use the Morph modifier to create an all laughing all singing character :).
Of course, if you have technical limitations (game engine...), then you will have to build a face rig.
03 March 2006, 04:17 PM
Probably i didnt explain myself well.. I can only use bones for my animation because of technical issue:) Thanks for the fast response :)
03 March 2006, 05:30 PM
Well, round the mouth is the sphincter muscle - a circular muscle, bridged at the sides. Its driven by the zigomatic majors, buchinator, and risorius. Its intersetion point is not fixed, unlike the frontals/brow. This unique muscle has many properties - it gets pulled by its neighbouring muscles, it can itslef compress "mm", it can pucker and importantly roll.using bones to emulate all thes controls whilst emulation volume preservation is not easy. Infact its very hard. The hardest area is interaction with hard body, ie muscle to bone/ rolling round the teeth.
Why you get the corners having those little crease is due to the order action of the muscles around it, the way there set in muscle .ie muscles with in muscles. And the order of and how there triggered. This order of muscles is very important, the zigo's pull the sphincter, which intern are pulling the riso's.Next to this are all the cheek muscles, zigomatic majors, that are linked dynamically to the sphincter. The sphincter is one circular strip, a muscle like the eye muscles the orbicularis oculi. How the zigo's and the sphincter bulge is based on triggers, like real muscles bicep, tricep. The insertion point and exit is important to.
So basically, what im doing is pseudo simulation/emulation of these muscles, but im using a facial 'map' of key areas - ie a mask of key muscle lines. With this system, i rig on a per face solution, and if needed to convert to bones, i just treat them as piggy backing the muscles. Theres a few other things, "tweaks" etc, but thats the jist of it.
03 March 2006, 03:11 AM
Eek, thanks for the explaination. So can i say that if i build the bone system according to the key muscle lines, I can simulate the muscle movement?
03 March 2006, 03:56 AM
Ummm.. kinda its a little more complex than that. Id do some research into it, watch lots of clips and study how your face moves and creases. Ive spent 3 years off and on, looking into - its no easy task.
03 March 2006, 08:16 AM
Hehe, words form the anatomy master.
It really takes a lot of study. Iīm just starting right now into the theory of muscles and how our body is moved by them. Hell, if we would have to think first before moving, weīd be lucky to bumble around like a bunch of zombies. Yeah, our body is one complex machine. And the facial muscles are a lot more complicated than for example a biceps muscle. I used this site in the beginning:
Itīs got small movies of the neccesary muscles and a good explanation of the anatomical syntax .
Another good resource is this one:
Itīs in german, but there are some nice Flash animations of all the facial muscles on it, where you can blend a skin layer in and out, so you get a good feeling how our face works.
03 March 2006, 10:29 AM
wao.. spending 3 years!:eek: Really an anatomy master :thumbsup:
Thanks for the resources dunkelzahn. It really help me to understand more on facial muscles.
Now the headache part will be translating to the bone system.. which probably will take me more than 3 years haha...
03 March 2006, 10:29 AM
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