couple things... 
1) this should be const, since it can't change after compilation
2) wouldn't it be cleaner to do this as sizeof() math... so for example... what if you did...

```
    const glm::vec3 position;
    const qint16 bodyYaw = 0;
    const qint16 bodyPitch = 0;
    const qint16 bodyRoll = 0;
    const qint16 targetScale = 0;
    const qint16 headYaw = 0;
    const qint16 headPitch = 0;
    const qint16 headRoll = 0;
    const float leanSideways = 0.0f;
    const float leanForward = 0.0f;
    const glm::vec3 lookAt;
    const float audioLoudness = 0.0f;
    
    const unsigned int offsetToChatMessageSize = sizeof(position) + sizeof(bodyYaw) + sizeof(bodyPitch) + 
                    sizeof(bodyRoll) + sizeof(targetScale) + sizeof(headYaw) + sizeof(headPitch) + sizeof(headRoll) +
                    sizeof(leanSideways) + sizeof(leanForward) + sizeof(lookAt) + sizeof(audioLoudness);
```