A simple UI I made based around the "recordAttr" mel command which records changes to specified attributes during playback as keyframes. A few similar scripts exist but this allows recording of custom attributes and use of Maya's native manipulators for easy workflow integration.
This kind of animation technique can be use for a variety of things but I find myself using it the most with facial animation, subtle/idle animation, or anytime something needs continuous movement over a large span of time.
- Paste the script into the Script Editor and save to shelf
- (Recommended) enable Frame Rate under Display>Heads Up Display
- Set the Playback Speed and Sample Rate. Sample Rate determines how often the viewport updates and a key is placed. Use lower sample rate values (more keyframes) when recording fast or complicated movement, or to provide more information for better fidelity when time remapping.
- Select the objects and what attributes you want to record in the Channel Box, click "Add From Channel Box." This will create record nodes for each of the selected attributes.
- Click START to playback the current time range and record any changes. You can stop playback either by pressing STOP or by simply stopping normally. (NOTE: Pressing START will overwrite any existing keyframes on attributes that are being recorded.)
- Click "Clear On Selected" to clear all record nodes on the selected objects. It's important to do this once the recording is complete to avoid unintentional keyframe overwriting. Also too many record nodes can reduce playback performance.