User Guide (Animation) - cmu462/Scotty3D GitHub Wiki

You can enter the animator mode by pressing a or A in any of the other modes. If you wish to edit the underlying skeleton of the mesh, you can toggle the ghosted (semi-transparent) mode by pressing g or G.

Rigging Action

You can enter the create joint action by pressing c or C after you enter animator mode. You can create new joints by first selecting a parent joint, then clicking anywhere else on the screen. From thereon, you can keep clicking on the screen to create a chain of joints. If you want to branch off at a joint, simply click on the joint to branch off of, then start another chain from there.

You can exit create joint action by pressing c/C again or pressing any other key that takes you into a different action.

Editing Skinning Weight Threshold Radius

Each joint has a radius associated with it which controls which part of the mesh it affects when it is animated. The radius is visualized by the blue capsule around each joint segment. You can press d or D to trigger the action which allows you to edit the radius of this capsule. After you enter Change Threshold Radius action, you can click on a joint and drag the mouse up or down while left clicking to change its threshold radius.

Posing Action

After laying out the skeleton and adjusting the skinning weight radius, you can start posing the character in the posing action. You can enter this action by pressing p or P. In posing action, you may select any joint and use the rotation widgets to change the joint angles.

Toggling Linear Blend Skinning with Threshold

You can press u or U to toggle between linear blend skinning with or without threshold.

Inverse Kinematics

Multiple targets can be specified for IK purposes. To specify an additional target, just select a new joint and right click. To clear all targets, press i or I.

Animation Keyframe

A new keyframe is created whenever you edit any of the objects in the scene. You should first select the appropriate time on the timeline below, before you make any changes to the objects in the scene. If you want to animate the characters, you should do that by animating the joints you created using the rigging action above. The joints are meant to be rotated only. You may cycle through different modes of editing by pressing the e or TAB key.

Saving the Skeleton and Animation

The read and write to buffer functions have been upgraded to also read and write the skeleton and animation information. Switch to mesh edit mode first, then press l for load or w for write and numbers from (0-9) to read or write your work.

Physical Simulation

Whenever the timeline is playing, a wave equation is simulated on all meshes in the scene, where the waves create a displacement of the mesh along the normal direction. Without any specified initial conditions, this won't change the mesh at all, but when conditions are specified this will give the appearance of waves propagating along the surface of the mesh. An offset is specified by using the wave action, triggered by pressing w or W, which will allow you to move vertices in the normal direction, to give them an initial offset, and to give a more natural looking result, will give a Gaussian smoothed offset to a neighborhood of the vertex. There is no way to keyframe waves or save state about the waves. To completely reset the offsets of the mesh, press z or Z. The wave simulation preserves the average offset across all vertices, so when a vertex is dragged up, others will move slightly down, and vice versa, in order to preserve this at 0.

There are 2 different integrators that can be used to simulate waves, Forward Euler and Symplectic Euler, and Forward Euler is chosen by default. Forward Euler is a less stable integration approximation, so waves simulated with it may blow up and produce unnatural results!

Additionally, different timesteps can be supplied, by using the + and - keys. Note that larger timesteps will usually lead to less stable results! Different damping factors can also be supplied by using SHIFT + + or -. A damping factor of 0.0 means there is no damping, and a value of 1.0 won't propagate any waves, it'll just smooth the mesh out until its back to its original shape.

KEY COMMANDS

Command	Key
Enter animate mode	A
Enter create joint action	C
Enter capsule radius edit action	D
Toggle ghosted mode (semi-transparent)	G
Enter Inverse Kinematics action	I
Return to mesh edit mode	M
Enter object edit action	O
Enter posing action	P
Toggle linear blend skinning with threshold	U
Enter wave action	W
Reset all wave offsets	Z
Raytrace Animation (From beginning)	N
Rasterize Animation (From beginning)	T
Cycle through different edit widgets in object edit action	E or Tab`
Increase / Decrease Timestep for Physical Simulation	PLUS/MINUS
Increase / Decrease Damping Factor for Physical Simulation	SHIFT + PLUS/MINUS
Change Simulation to use Forward Euler	F
Change Simulation to use Symplectic Euler	S
Edit a joint position	Toggle object transformation mode with C, then turn on ghosting with G, then click on a joint and use the transform widget to move it
Enable Symmetry	Shift+S
Change Symmetry Axis	Shift+X/Y/Z for X/Y/Z axes
Rotate camera	(left-click and drag on background)
Zoom camera	(mouse wheel)
Dolly (translate) camera	(right-click and drag on background)
Reach for Point under Cursor with IK	(right-click and hold in IK mode)

TIMELINE CONTROLS

Command	Key
Play / Pause	Space
Move Forward / Backwards	Right/Left
Step Forward / Backwards (One Frame)	ALT + Right/Left
Jump to Beginning / End	CTRL + Right/Left
Move to Next/Previous Keyframe	SHIFT + Right/Left
Increase / Decrease Timeline Length (1 second)	Up/Down
Toggle Looping	L
Make this frame a keyframe for Selected Object	K
Make thie frame a keyframe for All Objects	SHIFT + K
Delete Keyframe for Selected Object	Delete/Backspace
Delete Keyframe for All Objects	SHIFT + Delete/Backspace