Chapter 7: Natural Character Animation
Chapter Objectives:
- Use the Bone tool to build armatures (skeletons) of movie clips
- Use the Bone tool to build armatures of shapes
- Animate natural motion of armatures using inverse kinematics
- Constrain and pin the armature joints
- Edit the position of armature bones and joints
- Refine shape deformations with the Bind tool
- Simulate physics with the Spring feature
- Adjust the speed setting to add a sense of weight to armatures
Chapter 7: Exercise
- Read and Complete: Adobe Animate CC Classroom in a Book Chapter 7 Tutorial (Submit in the Network Drive When Complete)
Chapter 7: Project
Introduction
One of the more interesting concepts in animation is inverse kinematics. Inverse kinematics (IK from here on out) allows the animator to string together a series of objects and then move them all by manipulating the object on the tail end of the string. Imagine an leg made up of a thigh, shin and foot; traditional animation techniques would require one to animate each part individually in order to create a step. But with IK, all one needs to do is move the outer most object (the foot) and the shin and thigh follow along, pivoting at the joints. In Animate, we can accomplish IK with the new bone tool.
Use the Animate bone tool to link the parts of the mannequin (in the provided file) together. Then set constraints, and finally create a short animation in which the mannequin dances.
Project Files
Download and use the zipped file here.
Required Submission Files
Your final deliverables are the source .FLA document CALLED: Project7(YOUR INITIALS) Place the finished .fla in the Network Drive
Grading Rubric (5 Points)
You will be graded according to the following criteria:
- How compelling is the animation, from beginning to end.
- All bones are moving realistically as he’s dancing to the music.
- Does the project effectively use different layers to manage multiple images?
- Is the bone tool used appropriately and with good technique?
Instructions
- Download this zipped file; if contains a Flash file with a mannequin drawing. Open it up and observe that each body part is a separate movie clip. Note also that I’ve also set the pivot points for each part so that it will rotate at the joint, not the middle.
- Select the bone tool. Start in the center and work your way out. Click on the torso and drag to one of the upper arms; when you do that several things happen—a new layer called “Armature” is created, the objects you clicked-on are moved to that layer, and an IK bone appears running from the torso to the shoulder.
- Click on the upper arm and drag to the forearm to create the next bone. Then connect the forearm to the hand. For fun you can select the selection tool and give the hand a little shake—the whole arm should move (perhaps in ways a human arm shouldn’t! We’ll address this in a moment). If you managed to move the arm into a painful looking position, choose undo to go back to the way it was before you mangled his arm.
- Now link the other arm by doing he same thing on the other side—start at the torso and drag to the upper arm, then forearm, and finally the hand. Note that an object can have more than one IK bones extending from it (which is good, since our torso has two arms)
- To do the legs first drawn IK bone from the torso to the pelvis. From the hips draw IK bones down each leg, from the pelvis to the high, thigh to shin, shin to foot. Repeat for both legs.
- Finally, connect the head/neck to the torso in the same way.
- Okay he’s connected, but some of the body parts may have moved in front of parts they should be behind. To rearrange the stacking order, select a part to move and press command–up arrow or command–down arrow to move it forward or backward. Refer to the layer order to help you determine the stacking order.
- Delete all of the body parts layers since the parts have been moved to the armature layer.
Constraints
At this point you can drag on any outer body part and make your mannequin move. However, the movements might seem a bit unnatural at the moment. Let’s refine our connections so that he moves in a more lifelike way by adding constraints.
- Start with the torso. Select the torso and make sure the IK bones are showing. Select on of the IK bones that start in the torso (there should be four—one for each arm, one going to the pelvis, and one to the head). With the bone selected open the properties window and look for the Joint: Rotation property. Locate the Constraint check box below it and check it. Then set the Min and Max values both to zero; this will prevent the shoulders, neck, and pelvis from “floating” out of position (setting it once affects all four of the bones that start in the torso).
- Next move to the pelvis. The pelvis/hips should be able to shift some, but not too much. Rotate the pelvis counter-clockwise until you get to the point where you feel the hips should be at their limit (it’s a judgement call). Select the IK bone that goes to the right thigh and go to the properties window. Once again turn on the constraint property. Set the minimum value to zero—this should limit the pivot of the hips to the current point. Now rotate the hips the other direction until you reach what you feel should be their limit. Set the maximum to zero. You should now be able to pivot the pelvis, but only between the limits that you have set.
- In the same way, proceed to the upper arms, then forearms, then hands, thighs, shins, and finally feet, setting constraints for all. You want to allow for a realistic range of movement.
Gotta Dance!
- To animate movement of the IK bones is simple; advance the playhead to a point along the timeline and then move one or more bones. A movement keyframe is automatically added and the armature layer tweens between both points. You can move any number of the bones to create complex movement. Continue to move the playhead, changing the position of the bones as you go. See if you can get your guy to dance
Hints
- To move a bone without moving the inner connecting bone, hold down shift.
- Save and submit your project accordingly: .FLA document CALLED: Project7(YOUR INITIALS) Place the finished .fla in the Network Drive