> For the complete documentation index, see [llms.txt](https://docs.convai.com/api-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.convai.com/api-docs/plugins-and-integrations/convai-unity-sdk/core-concepts.md). # Core concepts Find explanations for how the Convai Unity SDK works at runtime — connections, sessions, embodiment, dialogue state, and event-driven responses. The Core Concepts section explains the systems that run beneath every Convai character in your scene — the runtime layers that manage connections, the session state machine that governs each character's lifecycle, the per-character embodiment layer that drives modules like Gaze and Emotion, the turn-taking system that controls who speaks and when, and the event components that let your scene react to what happens at runtime. Start with **Runtime architecture** if you are new to the SDK internals. Read the other pages when you need to configure a specific system or understand why the SDK behaves a certain way.
Runtime architecture
Runtime layers, interface inventory, and what you can replace.		Runtime architecture
Session lifecycle
State machine, per-character sessions, persistence, and reconnection.		Session lifecycle
Character embodiment
The per-character composition root, deterministic tick, and single-writer rules for Animator and facial blendshapes.		Character embodiment
Dialogue state
The eight-value dialogue state model every embodiment module reads.		Dialogue state
Asset ownership and copy-on-write
Why editing a package-shipped profile creates a project copy instead of editing in place.		Asset ownership and copy-on-write
Turn-taking modes
Hands-free vs. push-to-talk — every field and policy explained.		Turn-taking modes
Voice activity detection
Server default vs. custom detection thresholds resolved at connect time.		Voice activity detection
Event system
Relay components, payload types, and subscription patterns.		Event system
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