By trying to solve another problem, I’m trying to understand quaternions. But unreals function definition is just confusing in that regard.
FORCEINLINE FQuat FQuat::Inverse() const
{
checkSlow(IsNormalized());
return FQuat(-X, -Y, -Z, W);
}
According to Maths - Quaternion Functions - Martin Baker and multiple other sources, the function actually calculates the conjucate of a quaternion, not the inverse.