Bringing digital characters to life is one of the most exiting and rewarding fields of computer animation. For this reason you have invested into 3D Studio MAX, an industry standard for affordable and high-quality 3D computer animation. Armed with the manuals you are ready to learn all about animating monsters, space aliens and whatever unfortunate creature the Empire can't hide from you.
Bones sound like a good place to get started, but the manual covers the Bones System with a staggering one and a quarter pages. In later chapters you find additional information about bones and some examples on animating jointed characters (those build by linking separate objects at their joints). That's great for animating Mech-Warriors and all things mechanical, but you were hoping to animate your favorite space alien that you downloaded as a single mesh from the Net. No reason to get sweaty palms, just turn a few more pages and the manual will tell you how to do it. You reach the end of the chapter and turn back to start another search. At last, once you've gone through the whole manual page by page, you realize that even feature-packed software like 3D Studio MAX doesn't offer everything out of the box. You're probably not the first new owner to feel a little disappointed that you can't use bones in MAX to deform solid mesh objects. (You can use Linked XForm Modifiers to link the vertices in a mesh to a bone structure. However, the results are hardly worth spending time on and you can't actually use this technique to properly bend the mesh at a joint like a knee or elbow.)
To the rescue comes Character Studio 2.0 from Kinetix, equipped with all the tools you need to animate any type of two-legged creature. Character Studio comes in the form of two plug-ins for MAX: Biped and Physique.
A biped is a human-like skeleton made of linked boxes. Biped comes with its own native IK system and does not work with the standard IK controller in MAX. The advantage is that it offers additional features to help you produce your animations quicker and with realistic looking motions. The skeleton structure is a classic hierarchy of linked body parts. E.g. the head is linked to the neck, which is linked to the spine, which is linked to the pelvis (the root of all objects) etc.
Physique is a modifier that uses a linked structure such as a biped or MAX bones to deform a character's skin (or any other type of surface). It supports advanced features such as weighted blending, skin sliding, muscle bulging and tendon effects.
Unfortunately Character Studio is one of those MAX add-ons that have to be purchased separately. However, we are about to fire up our vertex-to-photon converter and find out whether Character Studio is a productivity tool that will enable you to quickly recover its purchase cost.
The list of improvements over previous versions is quite extensive and Character Studio 2 can now import motion capture data. Import filters 'intelligently' reduce the number of keyframes from imported motion sequences, making it easy to modify the keys for your own animation. Motion Flow mode lets you combine several animation clips into a single animation sequence. For instance, you could paste an imported motion capture sequence after your own keyframed animation and create a smooth transition between the two. Animation Layers make it easy to progressively add new layers and keyframes onto an existing animation without changing the original keyframes. Once you're happy with the way your character moves, you can collapse the layers into a single layer. This takes the concept of layers in Photoshop to change an image without destroying pixels into the world of computer animation and keyframes.
Character Studio 2 supports polygonal surfaces, patches and NURBS. Currently NURBS in MAX aren't blessed with speed and deforming a NURBS surface with Physique is painfully slow. The online manual offers a solution by suggesting to apply a Mesh Select modifier to your NURBS model before using Physique and that certainly speeds things up a lot (and your original surface keeps its NURBS status too).
Should the printed User's Guide ever slip your hands, you won't have to worry about damage to your toes. The 232 pages seem more like a supplement to the online reference, which in contrast is extensive and detailed. The online reference system has the same look and feel as its MAX kindred, making it a most effective tool at locating useful information. There are also some online tutorials - a must for every first-time user. Not enough though, in my opinion, to provide a thorough base of knowledge for beginners.
b i p e d
Creating a biped is as easy as creating a 3D primitive - simply click and drag the mouse. The Biped plug-in operates in three basic modes: Figure Mode, Footstep Mode and Motion Flow Mode. When you first create a biped, its creation parameters determine the basic structure of the skeleton. E.g. does your skeleton need a tail, how many fingers and toes etc. Once the biped is created, you'll find the biped rollout under the Motion panel. The next step is to load a mesh character and align its pelvis with the biped's center of mass (represented by a diamond-shaped object). Now hop into Figure Mode and use the standard MAX transformation tools to scale and rotate bones until they fit snugly inside the mesh. This procedure is relatively easy if the character was modeled in the correct position: arms outstretched, fingers spread and legs slightly apart. Once fitted inside the mesh, it's a good idea to save your scaled biped to a figure file so that you can load and reuse it should you ever need to animate a similar character.
As you'll find out later, using the Physique modifier and successfully deforming a mesh can be a bit daunting at first. It's basically a matter of practice until you get a feel for how Physique and its tools deform a character's skin. You'll probably find that after setting up a few characters you can achieve in 30 minutes what could easily take a whole day on your first try. Again, you can save all your Physique settings into a file. Should you need to animate a similar character, you just need to load your Physique parameters and modify them.
Your character is now ready for animation. If you are keyframe lazy, just load any one of the 300 odd motion capture files supplied with Character Studio 2. With a few mouse clicks you can have your character slip on a banana, do the cha-cha, Rock 'n Roll, Ballet, step into dog doo or just walk a few steps and sit down.
It's more fun to create your own animation though, and I found that Character Studio doesn't put any restrictions on the way you animate, nor does it force you to adopt a certain style. The quickest way to animate is to activate Footstep mode and get your character to walk, run or jump by simply placing footsteps in your scene. If that's where you leave it, then obviously the whole world will know that you used Character Studio for your animation. It takes little effort to personalize your walk by adding a few keyframes to get your hips to swing more expressively, the head to look around from side to side and break the monotonous forward and backward swing of the arms.
To animate your biped's torso (made up of spine links), his arms or head, you select any these parts and move or rotate them to a new position using the MAX transform tools. If you grab a hand, the arm will follow in standard IK tradition. You can either use the Animate button, or hit the 'Set Key' button on the Biped rollout whenever you need to create a new keyframe.
Animating with footsteps might not be your call and for this reason there is Freeform Animation. Just hit the Animate button after creating a biped, grab a hand or foot and start pulling - it's just you and the biped's IK system now. Certain features, like Biped Dynamics (you'll learn about them shortly), are disabled during Freeform animation. You can also convert footsteps into Freeform and visa versa. For the best of both worlds, insert a Freeform period right between your footsteps and do stuff that footsteps can't handle, like swimming through a crocodile invested river.
The IK Blend parameter controls the biped's behavior between two keyframes. Let's say your biped is attending a birthday party and wants to grab the last sausage off a plate. Your best chance of getting there in time is to move the hand in a straight line directly towards the target. Using default IK settings, the hand would move along a curved trajectory as the IK system calculates a smooth transition between keyframes. Changing the keys IK Blend value, you can get the hand to move in a direct path (IK Blend is basically a parameter that lets you blend the effects of inverse kinematics with forward kinematics). By switching on Trajectories, you can visually adjust the way an animated object moves. As with the standard MAX TCB controller, you can set Tension, Continuity, Bias, Ease To and Ease From for every key.
Body Dynamics help you to keep your character in a position where his feet can properly support his weight (if you ever stood on ice and had your feet slip from under your center of mass, you know what can happen!). If you bend the spine forward, biped will automatically shift his pelvis back to keep from 'falling over'. Dynamics Blend controls the amount of gravity when airborne. Should your character need to jump into the air, you don't need to create keyframes as the character leaves the ground, reaches the highest point and lands - it's all in the way you place footsteps, but more of that later. Ballistic Tension bends your character's knees in anticipation before he jumps and again when he lands.
Biped Dynamics work on the biped's center of mass, represented by three separate animation tracks in Track View - Body Vertical, Body Horizontal and Body Turning. For instance, the keys that make a character bob up and down as he runs away from Godzilla are placed into the Body Vertical track. Here you can modify them like all other keys in Track View.
Other animation keys are condensed into specific tracks. All the keys for the fingers, hands, lower and upper arms, for instance, are stored in the Clavicle track. Keys for the fingers will therefore appear in the same track as keys for the upper arm. I found this to be quite useful and it keeps things simple. If you need to create a detailed hand-finger animation, you can enable Separate Tracks in the Animation Properties roll-out to give you a separate track for all the fingers, the hand, lower arm and upper arm.
o n b l u e , p u t y o u r l e f t l e g f o r w a r d
Sooner or later your biped needs to interact with other objects in the scene and this is what Anchors are used for. Anchors are animatable attachments that link the arms or feet to a follow-object. When you anchor a biped’s hand to a dagger, you only need to move the dagger and the whole arm will follow. Another way to interact with objects is the MAX Link Controller. In this case the object is linked to the biped, e.g. a dagger linked to a hand will follow the hand until the link is passed to another object.
My first attempt at making a biped walk up to an object, stand still for a few seconds then turn around and walk away produced an Olympic record-breaking jump into the air. I guess that even a simple procedure like placing footsteps doesn't save you from reading the manual, so let's have a closer look:
Footsteps are colour coded, blue for the left foot and green for the right. Figure 01 and 02 show footsteps in the Perspective viewport and in Track View. In Track View you fine-tune footsteps to prevent neck-breaking jumps and other unwanted acrobatics. The blue / green blocks represent the time period the left / right foot touches the ground during a step. In the spaces between, the foot is moving through the air. The two numbers at the top of a block represent the frame number when the foot touches and leaves the ground. The bold number below is just the footstep number. To make my biped stand still, I lengthened footsteps 11 and 12 and by overlapping them, both feet remained on the ground. The reason for my biped's Olympic jump is revealed here as well. After getting the biped to stand still, I added some more footsteps to make him turn and walk away. This created an empty space after footsteps 11 and 12. Biped interprets this as a jump into the air, since neither the left or right foot is touching the ground. The solution was as simple as stretching blocks 11 and 12 to the right to close the gap between footsteps.
t h e r e ' s a b i p e d k n o c k i n g o n m y d o o r
The proof lies in the pudding and you usually don't get to taste all the sweet and sour plums of software tools until you use them on an actual project. To do that, I modeled a simple house scene. The goal was to make the biped walk up to the front door, enter the house, pick up a ball lying on the floor, put the ball into a shelf and finally sit down and relax inside a nice and comfortable couch (just what I'll be doing after this review).
I decided to act out my biped's movements a few times to get a better feel for what I wanted to achieve. Next I positioned my biped a few steps from and at a slight angle to the door and used 'Create Multiple Footsteps' to place 4 Footsteps. The Bend spinner bends a selected range of footsteps, making it easy to walk around corners etc. I adjusted the Bend amount until the footsteps were pointing towards the door. After activating the footsteps, you can press the Play button and watch your biped walk. With 'Create Footsteps (at current frame)' I placed another two footsteps to get the biped to stand in front the door with his feet together. The standard biped walk is a bit mechanical, so it's a good idea to modify it into a more expressive walk.
Getting the biped to stand still in front of the door was no problem. I stretched the end of the last two footsteps in Track View to the right, overlapping them for the amount of frames I wanted the biped to stand still. Next I went to the end of the 'stand' period, clicked 'Copy Pose' and pasted the biped's pose into the keyframes at the beginning of the 'stand' period. The biped's feet still wiggled a bit, which was eliminated by reducing the continuity of keys on either side of the standing period.
Next, the biped grips the doorknob, twist it and pushes the door open. Acting out the movements yourself is really essential here (as long as it's not something like falling off a skyscraper). Moving the biped's arms into position is relatively easy and I used the Move and Rotate tools to position the head, arms and upper body the way I wanted. If you double-click on the upper arm, all objects down the hierarchy are selected. Using the Copy and Paste Pose tools can reduce the time spend animating considerably by pasting existing poses into new keyframes and modifying them for a new situation.
Now it's time to pick up the ball. With 'Bend Links Mode' active, the whole spine curls naturally when rotating one of its links. I also pushed down the center of mass object a bit to bend the biped's knees. Maxi's Link Controller is useful to link an object to different objects over time. I used it to first link the ball to the floor at frame 0, then link the ball to the hand and finally link the ball to the shelve. In fig. 03 footsteps 19 to 22 are the biped walking up to the shelf. To make the biped turn around and walk away after depositing the ball, I appended Footstep 23, positioned it behind the biped and rotated it to point into the new direction. Next I added some more footsteps (24 onwards) and Biped Dynamics took care of creating a realistic turn - pretty simple.
To get the biped to walk up the stairs, I simply needed to place a footstep each onto their surface.
The last part of my animation was to get the biped to sit down on the sofa. For this I needed to disable Biped Dynamics and switch to Freeform Mode. The reason is that Biped Dynamics won't allow you to take the biped's feet off the footsteps (unless you're jumping).
At this point my enthusiasm for being about to finish my first Character Studio animation was dampened a bit when I found that I could no longer move the biped's left arm. After some investigating, I realized that the Link Controller was the culprit. It seems to have permanently replaced the hand's IK controller after the ball was no longer linked to it. The solution was to remove the time from the Link Controller at which the ball is linked to the hand, finish the animation and re-create the link afterwards - problem solved.
Right-clicking a footstep in Track View brings up the Footstep Mode dialog. Here you can create a freeform period between footsteps, which then shows up as a yellow line in Track View (fig. 04). Setting the Balance Factor in Body Dynamics to zero for the freeform period stops biped from shifting around his pelvis and you can keyframe a pose where his body weight is 'supported' by something like a chair. I only had to keyframe two poses to animate the biped sitting down and get comfortable in the sofa. All that was left to do now was to copy the 'sitting' pose to the end of the freeform period.
Well, there goes my first Character Studio animation and it wasn't hard work at all. The most difficult part was correct timing of the movements and that is something requiring experience, no matter what software you use. Now that I have my basic animation, I can go back, refine existing keyframes and add new ones to get more realistic and detailed movements. This is a good opportunity to make use of Animation Layers.
What I did above was perform my steps slightly out of order. It's best to follow the sequence of first fitting the biped inside a mesh, applying Physique and then animating the biped. I decided to test the flexibility of Character Studio when it comes to preventing repetitive work. Once my animation was completed, I saved it to a .bip file to see if I could reload it into a different biped once I had set up a complete character with Physique.
p h y s i q u e
Things get more complex when it's time to fit the biped inside a mesh and apply the Physique modifier. There are some good and detailed sample meshes of creatures and human figures that come with Character Studio, but I decided to look elsewhere for a victim. So; meet 'Hugo' - he escaped from Poser 2 disguised as a 3D Studio mesh and got caught trying to immigrate illegally into MAX. He was promptly assigned a multi sub-object material for better identification and given the option of either being sent back to Poser or volunteer to have a biped fitted inside his body. Luckily Hugo decided to go with the experiment and should he survive, he'll receive permanent MAX citizenship.
Characters exported from Poser 2 don't have much polygonal detail, so to make sure Hugo's joints bend properly, I applied a Mesh Smooth modifier to his elbows and knees.
All bipeds are created equal, but you can't say the same about all those 'meshy' characters out there. You therefore need to scale the proportions of a biped to fit inside the character's mesh. There really is no limit to what shape and size your two-legged mesh can come in, you can scale your biped to fit anything. I followed the basic procedure laid out in the on-line tutorial to scale my biped and things went quite smoothly. Let's say you zoom in on the fingers of the left hand to select and scale them. Using the Symmetrical Track Selection tool you can select the fingers on the opposite side without having to pan your viewports. Whatever transform you now apply to the left fingers is mirrored to the right fingers. With Copy and Paste Posture Opposite you can first scale on side of the body and then paste the changes to the other side. I found that the most amount of time was taken by fitting the biped's fingers inside their mesh counterparts. With a bit of practice, however, you can have a biped fitted to a skin within a few minutes.
Now its time to apply the Physique modifier and initialize it to the biped's pelvis (the root object). As you can see from fig. 05, Hugo looks a little rough around the edges now. Every bone in the biped is defined by a link (drawn as yellow lines) and every link has an associated envelope. Envelopes define a volume of space around which the link has influence over nearby vertices. Physique does create default envelopes, but they still need to be tuned for proper deformation.
Fig. 06 shows the envelopes around Hugo's upper and lower arms. They overlap at the joint and both envelopes can influence vertices in the overlapping area. The colour of the vertices indicates their deformation status. Red vertices are fully deformable. Green vertices are rigid and just follow the link they are assigned to (usually used for the head). Blue vertices indicate possible trouble, as Physique is not sure which link they should go with. Hugo's skin irregularities in fig. 05 are caused by unassigned blue vertices, but once all envelopes are properly scaled, Hugo should look like his good old self again. For every envelope you can adjust inner and outer Radial Scale and Parent and Child Overlap.
Once the envelopes fit, you'll still find weird deformations when animating your character. Fig. 07 shows the unwanted effect links can have on neighboring vertices that come too close. To correct this, you'll have to manually remove selected vertices from their influence. In Fig. 07 I removed the vertices of the left leg from the influence of links on the right leg, while the right leg itself is still being distorted. For good results, you need to perform the same procedure to all the links in the legs and fingers. It's a somewhat tedious job, but there is no getting around it.
Now that Hugo is ready for animation, I loaded my previously created .bip file. I found that my new biped was a little shorter than the one I used to create my animation. Footsteps loaded from the .bip file are re-scaled to fit the biped's height and the result was that my footsteps didn't quite fit the scene any more. What I needed to do was scale my whole biped uniformly without losing the Physique settings. The procedure for this is to disable the Physique modifier, rescale the biped in Figure Mode and reinitialize Physique to 'Initial Skeleton Pose' and tada; everything was in proper scale. Now I realized that my character's arms were longer too and his hands were moving through the doorknob. It didn't take very long to modify some of the keyframes to compensate for the longer arms and my conclusion is that Character Studio really does safe time when you animate characters of different size and proportions.
When you're happy with the way your mesh deforms, you can move on to some of the advanced features to add extra realism to your character. For instance, you might want your character's biceps to bulge when he bends his arms. Actually, creating bulges is rather simple. Place your character in a position where you want the bulge to be visible (arm bend like a body builder), go into Bulge sub-object mode and use the Bulge Editor to select a link (e.g. upper arm) and define a cross section. You can then visually adjust the amount of bulge and set an angle at which the bulge occurs. For even more realism, you can add tendon effects, which are also found in Physique's sub-object mode.
c h a r a c t e r s t u d i o a n d f a c i a l a n i m a t i o n
Character Studio can be used for facial animation too. The sample file 'snake.max' shows the head of a creature with an additional structure of links. Moving the dummy objects moves different parts of the face and I found the level of control over facial expressions rather impressive. I have to add though that the (very short) description on creating this particular linked structure is a bit confusing and a more detailed description would certainly be helpful.
You can even be inventive and break some of the two-legged biped restrictions. There is a sample figure file of a biped that has been re-shaped to fit an alligator's skin.
t o b u y - p e d o r n o t
Biped and Physique integrate seamlessly into the MAX user-interface and go well with the work flow. Character Studio 2 is certainly not a tool that forces you to adopt a certain style of animation and take the individual touch out of your work. It doesn't save you from learning the basics of character animation though. It is an effective tool that helps you accelerate the process of going from idea to animated story, but also makes it easier to produce garbage too. If you feel that animating two-legged characters is too restrictive, you can always set up your own bone structure and use Physique to handle mesh deformation. If you're into character animation, then Character Studio 2 is certainly a tool to consider - especially if your competition has got it.
Oh yes, in case you've been wondering; the Baby is still there!
|
Robin Lankes is the owner of Animatix Design, a South African based 3D animation company. If he's not busy torturing defenseless polygons, you might find him running his Siberian Huskies over endless sand roads on icy cold winter mornings.