Rope resolution inconsistency resulting in larger forces required

[inbilla]

Hi Jose,
I thought I'd return and offer my experience trying to implement this.
I think I've managed to acheive the behaviour I was looking for thanks to your pointers above  . 
I'm using the following logic:

Code:

private void ChangeVisualRopeLength(float newLength)
{
    if (!rope.isLoaded)
        return;

    // Current IPD is? (Ignore the start/end, they have pinned particles
    var endElementRestLength = rope.elements[0].restLength;
    endElementRestLength += rope.elements[rope.elements.Count - 1].restLength;
    var targetOtherElementLength = newLength - endElementRestLength;

    // Calculate the new IPD
    var currentIPD = rope.ropeBlueprint.interParticleDistance;
    var maxIPD = Mathf.Max(maxDesiredIPD, currentIPD);
    var stretchIPD = targetOtherElementLength / (rope.elements.Count - 2); // Don't touch the first and last elements
    stretchIPD = Mathf.Clamp(stretchIPD, 0, maxDesiredIPD);

    // Iterate trough all distance elements and update their rest lengths.
    var solver = rope.solver;
    var newElementRestLength = stretchIPD;
    rope.ropeBlueprint.interParticleDistance = newElementRestLength;
    int elementCount = rope.elements.Count;
    for (int i = 0; i < elementCount; ++i)
    {
        if (i == 0 || i == elementCount - 1)
        {
            // don't change rest lengths of first and last elements
            continue;
        }
        // Never shorten an element in this way (delete them instead)
        rope.elements[i].restLength = Mathf.Max(newElementRestLength, rope.elements[i].restLength);
    }
    // Update the mass of particles across the rope (except the ends)
    float totalActiveMass = newLength * massPerMeter;
    float massPerParticle = totalActiveMass / rope.particleCount;
    for (int i = 0; i < rope.particleCount; ++i)
    {
        if (i < 2 || i > rope.particleCount - 2)
        {
            // don't change rest lengths of first and last elements
            continue;
        }
        var solverIndex = rope.solverIndices[i];
        solver.invMasses[solverIndex] = ObiUtils.MassToInvMass(massPerParticle);
    }

    // Recalculate rest length as the cached value is used during ChangeLength
    rope.RecalculateRestLength();

    // Finally, tell ObiCursor to add/remove particles as required
    ropeCursor.ChangeLength(newLength);
}

Then I'm increasing the length whenever the real length deviates too far from the intended rest length:

Code:

private void FixedUpdate()
{
    float actualLength = rope.CalculateLength();
    float restLength = rope.restLength;
    if (actualLength - restLength > stretchThreshold)
    {
        if (restLength < maxLength)
        {
            float newLength = Mathf.Min(maxLength, actualLength + extensionRate * Time.fixedDeltaTime);
            ChangeVisualHoseLength(newLength);
        }
    }
}

Thanks for your help!
I'd be interested in any feedback you have on the above code if you observe any obvious problems.
Again, thanks for your help.