Animation and Simulation

Before starting working with the human body within my work. i thought i would do a bit of research on basic human anatomy. With added research i think it will make it easier for me to understand how to build/animate if needs be.

Skeletal System

the skeleton contains all of the bodies 206 bones and joints .

the purpose of the skeleton is to act as a support for the body and to protect the body from what else it is made up of for example the muscles.

Muscles

The muscles are responsible for the movement within your body. muscles vary within your body but each have important tasks such as making it possible for you to digest, talk, breath and walk.

We started our work in the first week reading the assignment brief and we needed to create a CAT rig and skin it to a character that we have be given. we were given the spider man rig and we started the basic process.

spider cap

After working on that rig for a small amount of time there were faults pointed out by our lecturer and so he supplied us with a new mesh that would be smoother and less hassle to work with. we were given a zombie to work with and i was happy not just because it would be a mesh that worked fully but zombies are a lot cooler than spider man.

we were also given an animation that would stretch every possible movement with the mesh to the max so that when we come to add our own, the mesh shoud look perfect. With the animation you could see that the mesh was reacting to the moving rig but it doesnt just work like magic, we would have to spend a lot of time fixing the mesh.

to change the way the mesh reacted, we had to select the vertices we want to manipulate and change the weight on how it is affected dependent on the bone we want it to be affected by.

I started with the feet as that what is affected by the animation first but i think it is always sensible to work your way up. we were told to only work on one side of the body as there is a process of copying limbs later that will come in useful for legs and arms. as the character is wearing shoes i wanted to restrict the stretch that was in the animation as shoes are rather rigid and normally reduce your foots bending movements.

week 1 capture foot 1

Working my way up the leg, i rounder off the knee bend as it was very pointy. by selecting two of the vertices, i could create a loop and when i change the weight to affect the movement, it would act as a ring and that way you can keep it even. it is a good trick with cylinder parts of your body.
back knee 2 back knee 1

bottomThe top half of the body was still looking poor with vertices sticking out all over so i decided to quickly weight the certain areas influenced by the bone.

bellyMuscle man

We started to look at muscles within the cat rig system. we found that you can link muscles to bones for a more realistic movement.

mucle add

even in the simple animation you can see the muscle crunch in here..
stretch1 stretch2

stretch out here as the neck muscle is still crunched..

stretch3You can see both sets of muscles responding to the animation and stretching accordingly.

Continued Zombie rigging

armpit

After sectioning off parts of the body with the certain bones, i came to what is probably the hardest part of the mesh to rig. you can see under the armpit on the image above, there is a gap. we were told that it is better to have and overlap than a blatant gap between the two body parts so this was when i knew i would have to really fiddle with individual vertices to get the best results. you can see below that the problem was fixed.
armpit fix

Moving onto the top of the shoulder, after a long time with trial and error, i managed to get past the awkward joint and more further down the arm where the vertices would be in bulk with a good amount of weight as it is a bone and can not be twisted as much.
shoulder

Getting the wrist to be able to move but to avoid the arm being twisted like a knot was i big challenge i fell and i one that i am still not overly pleased with but after doing the action myself and making other people perform, i didnt know what else i could of done. if i stopped the twisting then the wrist would be almost immovable so i had to find a reasonable balance. wrist hand

The hand would remain sturdy but all the fingers would prove tricky, and they did! The way i tackled it was i would give no weight affect on any of the fingers so they would not move with the animation and i would skin them individually. the problem i faced was that when i completed one finger and moved onto the next, it would assign effect onto the different digits bones and the other fingers mesh would be dragged down when the bones are animated. it wasn’t a major issue just a lot of hassle and time that i did not expect.finger tip middle of finger finger base finger thumb

When it came to the thumb, all other aspects of the hand were rigged so it wasn’t to difficult. i did however restrict some of the movement on purpose as i feel it looked accurate even though the animation pushes the bone a little further .

We used a separate mesh for the head so we had to add the skin modifier on again and add the appropriate bones  .

bottom of head

I started off by fixing it to the rest of the body so it lokked like it was attche like how it should be. even on a zombie. i took the top spine bone and fixed the top weight and all the bottom vertices in a loop.
head

I next to the head and used the drawing loop tool to grab all of the vertices on the head and round the bottom of the chin area as that should not be moved.neck

The main part was to link the fixed parts of the top and bottom of the head with the neck so it looked like a smooth process when linked with he animation. it took a short while to get things looking good and a lot was trial and error. but common sense really it can just get a bit confusing when your dealing the a mesh, and sometimes because it is low poly, it feels a bit sharp but most the time it is fixed up and sometimes it can’t really be helped.

These are my rendered images the are fully skinned and rigged up with a human bone structure.

FRONT

Zombie rig skin render front

SideZombie rig skin render side

TOPZombie rig skin render top

I made the skin mesh more transparent so you could see the rig.

This is a video showing off the range of motion. i have added a moving camera 50 mm lens and also some 3 point lighting to fit the scene.

We had to show of other animation using the rig so i created a short jog cycle adapting the pre set animations that are available for certain cat rigs in 3ds max.

Final animation

The final animation that i created was a short scene of a point of view or a hand held camera shot of the zombie hearing a sound, turning round, the person gets scare and falls on their back and the zombie is standing over them. i was really enjoying playing with the camera and animating the rig but towards the end, things started going slightly wrong and i may have done something to upset the mesh because it started playing up. i would of liked to develop it further adding more walking and trying to perfect the zombie motion. i tried practicing but i am not a very good zombie actor. the end of the video could be developed further with facial rigging and animation. it is something to think about.

I tried to get a good camera angle and i think it worked in terms with the scne but it is on line with the walk cycle and i tried to add a zombie walk onto it by dragging the left leg like it doesn’t function but you can’t see it very well at this angle.

MUSCLES CONTINUED

Skinning this character was different to the zombie as to start with, it is more hi poly, which should be good as it is more detailed but there is more to work with and more to potentially go wrong. we are not just skinning with the bones in the rig, the muscles are also influencing the mesh.

 

The two that i added were the Pectoral and the Trapezius muscles.

muscle see through

As there are too many vertices in a high poly mesh like this, it would be silly to affect them all like we did the zombie so we used the paint brush tool. you can set the size of the brush you want, and how intense it will be in terms of affecting the mesh and then you pretty much draw onto the skin. Each method has its high and lows but it a good way of targeting areas without worrying about backfacing etc.

you see here i am weighting the pectoral muscle

muscle man pecanother useful tool was the blend weights tool for smoothing.

muscle man underarm

Here are my skinned rig and muscles demonstrated by an animation

I have also added a wired version so you can see more clearly how the muscles are affected.

Facial animation

Morph targets

zbrush ape

Using simple tools (as i am not used to using z brush) we created different morph targets which are just different expressions made by individual parts of the face.

We exported them out of z brush and then imported into max to blend with the natural looking default obj. We were told two ways how to manipulate sliders to animating the face but this was the way i liked so much so that i can’t even remember the other way. The way i prefer is using the reaction manager. You add a ‘master’ which is the slider tool of your choice and a ‘slave’ which is the specific facial expression. one you have done that you put the slider where you want each expression to be moved to and create a state. slide the tool to the other end adding another state with the opposite value so for example when the slider is at one end it is the default, and at the other end the facial expression. the slider creates a smooth transition that blends the two and it can also be key framed.

morph target slider reaction manager

 

This is an animation of some of the expressions created by morph targets

 

This is a video screen capture of me demonstrating the slider system for the morph targets.

Bones

 

 

For this method of facial animation, i would use a different approach of how i get the certain facial expressions. unlike the morph targets, i would add bones to the head and jaw and use the skin modifier and fix the mesh appropriately. i used a short range of motion so i could have reference on fixing the mesh and then i would add adjustment layers onto the animation to animate the certain bones like the mouth and the eye brows. Although i was new to z brush, the time it took to get a basic expression was nothing compared to doing it with bones. a lot of problems i had were coming back to it and adding more bones for example the nose, and it would mess up or disrupt the rest when working in the layer manager. you can see that it is a powerful tool in animating and when skilled enough you will have total control in the facial movements. adding the individual motions to the sliders works in a similar way to the morph targets as you select the master and the slave but you have to select the base of the rig and select the adjustment layers depending on their global weight.adjustment layer animation

Here is a simple animation showing off some of the bone facial animations

Here is a video showing the sliders affecting the facial bones.

 

About philb15anim

studying computer animation and special effects at leeds met university
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