Body language

Find guides for adding ambient posture, breathing, weight shifts, and small reactive movements that keep a Convai character's body alive between animations.

Body Language is the Convai embodiment module that gives a character continuous, ambient nonverbal behavior: breathing, weight shifts, small gestures, and reactive flinches that never stop between authored actions. Body Animation plays authored clips — a walk cycle, a wave — and Body Language never owns a clip; it only adds small procedural motion on top of whatever the character is already doing. One component, ConvaiBodyLanguageController, drives all of it.

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What body language gives a character

Behavior	What it looks like
Breathing	The chest and shoulders expand and contract on a continuous cycle, with occasional sharper intakes on interruption, a settling sigh, and a deeper breath before the character starts speaking.
Weight shifts and sway	The character periodically transfers its weight between feet and drifts gently on the spot, the way a standing body constantly micro-balances rather than holding perfectly still.
Gesticulation	While speaking, small head beats and posture pulses ride the character's speech rhythm, and its hands stay subtly alive between authored gestures instead of sitting rigid.
Listening posture	While listening, the character leans in slightly and settles into stillness, with an occasional attentive head tilt.
Fidgets	While idle or thinking, a slow lateral weight shift keeps the character from looking frozen.
Reactions	A sudden emotion spike — surprise, amusement — can trigger a one-shot startle flinch or an amused bounce.

Add ConvaiBodyLanguageController to a character through Convai > Embodiment > Body Language and it works immediately on the SDK's built-in tuning — no profile asset is required to see breathing and weight shifts in Play mode.

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How it differs from body animation

Body Animation and Body Language both move the character's skeleton, but they solve different problems and never fight over the same motion:

	Body Animation	Body Language
What it plays	Authored clips: idles, walk cycles, talk overlays, actions, pointing	No clips at all — continuous procedural motion computed every tick
What it owns	The character's locomotion and any deliberate, recognizable motion	Ambient life layered on top: breathing, weight shift, posture, small gestures
How the two combine	Plays its clip through the PlayableGraph as usual	Adds small, swing-only deltas on top of whatever Body Animation already posed

A character can carry either module alone, or both together. When both are present, Body Language reduces itself rather than overriding Body Animation — see How body language works for the suppression rule that makes this coexistence reliable.

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Where to start

Body language quick start

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Explore body language

How body language works The behavior directors that produce this motion, and how it yields to scripted gestures.

Body language quick start Add the component to a character and see breathing, weight shift, and idle life running.

Tune expressiveness Make a character subtle or theatrical with the ExpressivenessPreset dial and per-behavior gains.

Trigger gestures and reactions Request a scripted head gesture, a semantic gesture cue, or a one-shot reaction from code.

Body language profile reference Every ConvaiBodyLanguageProfile field, grouped by section, with defaults.

Body language scripting reference The ConvaiBodyLanguageController public API: readings, handles, and enums.

Troubleshoot body language No motion, motion fighting a scripted animation, and refused gesture requests.