UpperArmsDistance's meaning is not consistent and likely introducing error

[sclark39]

In the first set of code, UpperArmsDistance appears to be the distance from the shoulder center to the distinct shoulder:

UBIKSolver/Source/UBIKRuntime/Private/UBIK.cpp

Line 11 in acc72b6

Settings.ArmLength = (Calibration.Height / 2.0f) - Calibration.UpperArmsDistance;

But in the distinct shoulder rotation solver, there is a divide by two on the UpperArmsDistance. Indicating in this spot that it is meant to indicate the distance between the distinct shoulders, not the distance from shoulder center to distinct shoulder:

UBIKSolver/Source/UBIKRuntime/Private/AnimNode_UBIKSolver.cpp

Line 421 in acc72b6

const FVector InitialUpperArmTranslation = FVector::RightVector * Settings.UpperArmsDistance / (2.f * Sign);

This is likely throwing off your shoulder rotation solve. To fix this, either the ArmLength should be calculated as:
Settings.ArmLength = (Calibration.Height - Calibration.UpperArmsDistance) / 2.0f;

OR the divide by two should be removed:
const FVector InitialUpperArmTranslation = FVector::RightVector * Settings.UpperArmsDistance * Sign;

[JonasMolgaard]

It's been a while since I looked at the code. It sounds correct what you say. Unfortunately I don't have access to my VR setup at the moment, so I can't verify it myself. Should someone else have a chance to make the change and verify it, i'll make sure to approve the pullrequest.