Troubleshoot emotion

Fix common emotion problems — expressions not appearing, state locked unintentionally, morph target mismatches, and offset changes with no visible effect.

Most emotion problems fall into one of three categories: no On Emotion State Changed event firing at all, the event firing but no face movement, or state stuck due to a lock. Start by adding a Print String inside your On Emotion State Changed handler — this one signal identifies whether the issue is in the session/signal path or in the morph target application.

Inspecting live state

The UConvaiChatbotComponent exposes emotion state you can query at any time from Blueprint during Play In Editor, without additional tooling.

What to check	How to check it	What it tells you
Whether the event fires	Add Print String inside On Emotion State Changed	If it never fires, the session is not delivering emotion data or Lock Emotion State is blocking server updates
Current score for a specific emotion	Call Get Emotion Score and connect to Print Float	A value above 0.0 confirms that emotion is active
Whether state is locked	Print the Lock Emotion State bool property	true means server updates and server-driven events are suppressed

To verify morph target mappings without relying on live conversation, call Force Set Emotion from BeginPlay, a temporary Blueprint input or test event, or a custom editor-callable wrapper function that calls Force Set Emotion. Then check whether Get Emotion Score returns the expected value and your Set Morph Target nodes respond.

Lock Emotion State is a replicated property. If you set it to true during testing, confirm it is reset to false before shipping — a locked state silently suppresses all live emotion response with no runtime error.

First-line investigation

Work through this checklist in order when emotion is not behaving as expected. Most issues resolve at step 1 or 2.

1

Confirm the session is active

The Convai Chatbot component must have a valid Character ID and be able to reach Convai. If there is no active session, emotion data is never sent.

• Speak to the character normally and confirm it responds with audio. If audio is absent, fix the session first.
• If audio works but the emotion event still never fires, export diagnostics and review the connection logs before escalating the character configuration to Convai support.

2

Check whether On Emotion State Changed fires

Add a Print String node inside the On Emotion State Changed event handler. Enter Play In Editor and speak to the character.

• Print String fires → The signal path is healthy. Skip to step 4.
• Print String never fires → The event is not reaching your handler. Continue to step 3.

3

Check Lock Emotion State

When Lock Emotion State is true, server-driven updates are discarded and On Emotion State Changed does not fire for those updates.

• Lock Emotion State is true → Set it to false to resume server updates and events.
• Lock Emotion State is false → The issue is upstream. Confirm the chatbot component has a valid Character ID and the plugin can reach Convai.

4

Check emotion scores

In your event handler, call Get Emotion Score for the emotion you expect and print the return value. Confirm:

1. The score rises above 0.0 when the character speaks with emotional content. If the score stays at 0.0, Emotion Offset may be suppressing values — see Offset changes have no visible effect.
2. The server label Convai sends matches one of the recognized labels — see How the emotion system works.

5

Confirm Set Morph Target targets the correct mesh

If scores are above 0.0 but the face does not move:

1. Confirm the Morph Target Name on each Set Morph Target node matches a name on the character's Skeletal Mesh exactly. Open the Skeletal Mesh asset and check the Morph Targets tab. Name mismatches cause Set Morph Target to silently do nothing.
2. If the character uses multiple Skeletal Mesh components (body, head, hair), confirm each Set Morph Target call targets the mesh that owns the morph targets.

After completing the checklist, if Print String fires on On Emotion State Changed, Get Emotion Score returns values above 0.0, and morph targets update on the correct mesh, the pipeline is healthy.

Common issues quick reference

Symptom	Most likely cause	Fix	Verify
On Emotion State Changed never fires	No active Convai session, no emotion packet for the response, or Lock Emotion State is true	Check Character ID, API key, connection diagnostics, and lock state	Speak to the character — the event fires and scores rise above 0.0
Event fires; face does not change	Morph target name mismatch	Compare Set Morph Target names against Morph Targets tab on Skeletal Mesh	Morph target values change in the Details panel when scores rise
Event fires; Get Emotion Score stays at 0.0	Emotion Offset suppressing scores, unrecognized server label, or Reset Emotion State with no new update	Check Emotion Offset value; speak to trigger a new update; verify server label	Get Emotion Score returns a value above 0.0 on the next server update
Character always shows the same expression	Lock Emotion State is true	Set Lock Emotion State to false	Expression changes with new speech after unlock
Force Set Emotion has no visible result	Morph target mismatch or handler not applying scores	Confirm handler runs with Print String; verify Get Emotion Score and morph target names	Forced score matches the intensity multiplier and the face updates
Offset change has no visible effect	Offset only applies when a new server update arrives	Speak to the character to trigger a new emotion update	Get Emotion Score reflects the new bias on the next update

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Expressions never change during conversation

Symptom: The character speaks but its face shows no emotional expression changes. On Emotion State Changed never fires.

Cause: No active Convai session, Convai is not sending emotion data for this character, or Lock Emotion State is blocking server-driven updates and events.

Fix:

1. Confirm the Convai Chatbot component has a valid Character ID and the plugin can reach Convai.
2. Set Lock Emotion State to false.
3. Add a Print String node inside the On Emotion State Changed handler to confirm whether the event reaches your graph.
4. If audio works but the event still never fires, export diagnostics and review connection logs.

Verify: Speak to the character — On Emotion State Changed fires and Get Emotion Score returns values above 0.0 for active emotions.

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The On Emotion State Changed event fires but the face does not change

Symptom: The Print String inside the handler fires, but no morph targets update on the mesh.

Cause: Scores are zero, morph target names do not match the Skeletal Mesh, or Set Morph Target targets the wrong mesh component.

Fix:

1. Call Get Emotion Score in the handler and print the return value. If the score is 0.0, check Emotion Offset and whether a Reset Emotion State call earlier in the session zeroed the scores without a subsequent server update.
2. Confirm the Morph Target Name on each Set Morph Target node matches the morph target names on the Skeletal Mesh. Open the Skeletal Mesh asset, switch to the Morph Targets tab, and compare the listed names.
3. Confirm Set Morph Target targets the Skeletal Mesh Component that owns the morph targets.

Verify: When Get Emotion Score rises above 0.0, the corresponding morph target value changes on the Skeletal Mesh in the Details panel during Play In Editor.

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Emotion state is stuck and server updates have no effect

Symptom: The character always displays the same expression regardless of its speech content. Server-driven updates appear to have no effect.

Cause: Lock Emotion State is true, or a repeated Force Set Emotion call overwrites every server update.

Fix:

1. Set Lock Emotion State to false on the Convai Chatbot component. Print the boolean in Blueprint to confirm the value at runtime.
2. Search your Blueprint graphs for Force Set Emotion calls triggered on Tick or on every response. Remove or gate those calls so server updates can apply.

Verify: Set Lock Emotion State to false, speak to the character, and confirm On Emotion State Changed fires with changing scores.

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Force Set Emotion does not visibly update the face

Symptom: Force Set Emotion is called from Blueprint but the character's expression does not change.

Cause: The event handler is not applying scores to morph targets, Reset Other Emotions is set unexpectedly, or morph target names do not match the mesh.

Fix:

1. Add a Print String inside On Emotion State Changed to confirm the handler runs. Call Get Emotion Score for the forced emotion — the return value should match the intensity multiplier (0.25, 0.60, or 1.00).
2. Confirm Reset Other Emotions is set as intended. If false, the forced score merges with existing scores and may not produce a visible change.
3. Confirm your Set Morph Target nodes use morph target names that exist on the Skeletal Mesh.

Verify: After Force Set Emotion, Get Emotion Score returns the expected value and the mapped morph target updates in the viewport.

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Offset changes have no visible effect

Symptom: Changing Emotion Offset on the component does not noticeably change expression intensity.

Cause: Emotion Offset applies only when a new server-driven update arrives, not retroactively. It also does not apply to scores set via Force Set Emotion.

Fix:

1. Speak to the character to trigger a new server emotion update after changing the offset.
2. Confirm the offset value is reasonable. Scores clamp to 0.0–1.0 — extreme offsets may saturate or zero all scores.
3. To test a forced expression, use Force Set Emotion with a higher intensity level instead of relying on offset.

Verify: Speak to the character after changing the offset — Get Emotion Score reflects the new bias on the next server update.

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Diagnostic flowchart

Use this flowchart when the text checklist does not isolate the problem. Start at the symptom, then follow the branch that matches what you observe in Play In Editor.

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Related pages

How the emotion system worksEmotion Blueprint referenceEmotion quick startEmotion examples