An Animation clip is a specialized Simulation event used for loading new animation into Atoms Crowd. The animation clip will get its motion data from an fbx or atomsclip file.
Users can tweak their clips by editing the following values:
- Event Name, the name of the animation clip.
- Clip path, the path to the clip file.
- Additive Mode, the additive mode for this clip. Additive mode can be: "None", "Bind" or "Reference". If None, this clip plays has a normal clip. If Bind, this clip will be evaluated as the difference of the animation values of the given file and the bind pose. If Reference, you will have to provide a reference clip file, this clip will be evaluated as the difference of the two clip files. Additive clips are used only within a state machine.
- Blend Frames After foot up, the number of frames used for blending after the foot leaves the down state.
- Loop, if the clip is a loopable clip. When this is off the animation clip becomes a "one shot clip". This will affect the behaviour of any state (state machine) using this clip.
- Start and End frames of your clips.
- Loop Blend, the number of frames used to blend when looping.
- Idle, this option does not do anything from version 2.4.0 and it will be removed in the next version of Atoms. Until version 2.3.0, if the clip is a idle clip or not. If Idle is on, the foot lock system will be disabled when playing this clip.
- Disable Foot Lock, If this option is on, the foot lock system will be disabled when playing this clip.
- Direction type: static, pelvis, joints or clip. Static: the clip will use as direction to the vector specified in the Direction field. Pelvis: the clip will use the pelvis velocity as direction. Joints: the direction of the clip will be the vector travelling from the first joint to the second joint (the joint ids are selected with the Direction Joints field). Clip: the direction is taken from the "clipDirection" metadata stored on the root pelvis joint.
- Direction, the direction used when the direction type is set to static.
- Direction Joints, the two joints ids used for defining the direction vector when the direction type is set to joints. The button on the right will show a pop up dialog to help you find the right joints id for a given agent type.
- Compatible Agent Type, the agent type compatible with this clip. This field is mandatory if you wish to retarget this clip onto a non compatible agent type.
- Transitions Frames, for long clips you might have different transition frames.
You can either enter them manually with a comma separated string (i.e. "10 , 50, 100") or let Atoms guess them for you by pressing the Auto button. Once pressed the field will be populated, but you will still be able to edit the string. If you don't specify transition frames only the loop end frame of the clip will be used. If you set -1 then every frame is used as a valid transition frame.
Transition Frames are used by state machines only. - Foot down data, the foot down state can now be edited directly inside the Atoms UI (from Atoms Crowd 2.0). Click on the "Load From Clip" button to load the graphs for each foot. You can edit the graphs and the changes will be stored in your animation clip as soon as it is registered. The foot down curves can also be computed automatically using the foot velocity or a ground height value, after the values have been computed users can still edit the curves.
Preview
The preview widget displays the animation for the selected clip. At the bottom you have controls for playing/scrubbing the animation and a control for changing the joint size.
Yellow circles appearing under the feet show the foot down state for each foot (this also reflecting the changes users might apply to the foot down data).
By right-clicking on the viewport, a menu will appear with the following options:
- set Set start frame: set the Loop Start field with the current frame value
- set Set end frame: set the Loop End field with the current frame value
- Use UI frame range: the preview will only display the frame range provided as input in the UI.
- Draw grid: enable/disable the grid in the viewport display
- Draw Joint Axis: enable/disable the joint axis in the display
- Lock Camera: enable/disable the locking on the camera
- Reset Camera: resets the translation/rotation of the camera
- Test Loop: enable/disable the animation clip looping
Navigation Controls:
- Alt + left click and drag: Rotate camera
- Alt + middle click and drag: Pan camera
- Alt + right click and drag: zoom camera
The clip direction
You might wonder why you need to set a direction for your clips. This is actually quite important, in fact if you set a wrong static direction for a clip you might end up having your agents going in the wrong direction.
Also it's important to understand that clips for a character should all share the same direction when used in a state machine, except few particular cases.
Your clip direction tells Atoms how your clip moves in space.
Atoms uses the clip direction to rotate your agent and match the actual agent direction (travelling direction) which is computed at each frame. For instance, if your clip is travelling mainly on the Z axis and you set the direction to be the X axis, you will see your agents rotated of 90 degrees on the Y axis later and they will move in the wrong direction.
Please check the Animation Clip chapter to understand better how to set up your agent direction.