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Help  Issues After Upgrading to Obi Rope 7: Bounciness, Jitter, and Rope Generation Problem
#1
Hello,

I recently upgraded to Obi Rope 7 and encountered a few issues issues with the ropes not behaving as they did in Obi Rope 6. I've kept the same settings from Obi 6 and am using the default settings for the new solver options (except for substeps, which I set to match the value I used in the Obi Fixed Updater).

In my game, the player can shoot ropes. I originally based this mechanic on the Extendable Grappling Hook script provided with Obi Rope, although I've modified it over time. After upgrading to Obi 7, I found that I could no longer shoot ropes at all. I noticed the Extendable Grappling Hook script had changed since Obi 6, so I tried to apply similar changes to my custom rope generation script. This allowed rope generation to work again, but I'm not sure if I implemented it correctly, and I suspect this might be related to some of the issues I'm experiencing (particularly issues 2 & 3 below).

I've attached a video showing the differences between Obi 6 and Obi 7.



There are the issues I'm having:
  1. Increased Rope Bounciness:
    • When lifting certain rigidbodies, the ropes are much more bouncy than they were in Obi 6.
  2. Rope Flashing in the Wrong Location:
    • Occasionally, when generating a rope, it momentarily appears to connect from the player’s hand to the world origin for one frame.
  3. Unpredictable Behavior When Shooting Ropes at Rigidbodies:
    • When shooting ropes at rigidbodies (e.g., a box), the behavior is inconsistent. Sometimes the box is lifted into the air or pushed around unexpectedly. I think this might be related to the issue mentioned above.
  4. Increased Rope Jitter:
    • When ropes are left to settle, there seems to be more residual movement in Obi 7 compared to Obi 6. I'm using the same sleep threshold in both versions.
This is my Rope Generation script. (For now I've modified the Change length method in ObiCursor so that I can just pass in the new length rather than the length change)
Code:
public class RopeGenerator : MonoBehaviour{
        public float breakThreshhold = 0.1f;
        public float extraRopeLengthOnSpawn = 0;
        [SerializeField] private bool _useTearing;
        [SerializeField] private float _tearResistance = 800;

        [Range(0, 2)]
        [SerializeField] private float _stretchingScale = 1;
       
        public ObiSolver solver;
        public Material material;
        public ObiRopeSection section;

        [Range(0, 1)]
        public float hookResolution = 0.5f;

        //public float hookExtendRetractSpeed = 2;

        [FormerlySerializedAs("hookShootSpeed")]
        public float ropeShootSpeed = 1;

        public int particlePoolSize = 100;

        public float ropeParticleInverseMass = 100.0f;

        //public ObiRope rope;
        [SerializeField] private float ropeThickness = 0.5f;
        [SerializeField] private float cursorParticle = 4f;
        [SerializeField] private float sourceParticle = 2f;
        [SerializeField] private bool particleRendererOn = false;
        [SerializeField] private bool _useSurfaceCollision;
       
        public void InitialiseRope(RopeData ropeData, Action ropeInitialised = null) {
            if (ropeData.IsInitialised) {
                return;
            }
            // Setup a blueprint for the rope:
            ropeData.Blueprint = ScriptableObject.CreateInstance<ObiRopeBlueprint>();
            ropeData.Blueprint.resolution = hookResolution;
            ropeData.Blueprint.pooledParticles = particlePoolSize;

            // Create both the rope and the solver:    
            ropeData.ObiRope = ropeData.RopeObject.AddComponent<ObiRope>();
            ropeData.RopeObject.AddComponent<ObiParticleRenderer>().enabled = particleRendererOn;

            ObiRopeExtrudedRenderer ropeRenderer = ropeData.RopeObject.AddComponent<ObiRopeExtrudedRenderer>();
            ropeRenderer.section = section;
            ropeRenderer.uvScale = new Vector2(1, 4);
            ropeRenderer.normalizeV = false;
            ropeRenderer.uvAnchor = 1;
            ropeRenderer.material = material;
            //ropeData.RopeObject.GetComponent<MeshRenderer>().material = material;

            // Tweak rope parameters:
            ropeData.ObiRope.maxBending = 0.02f;

            // Add a cursor to be able to change rope length:
            ropeData.Cursor = ropeData.RopeObject.AddComponent<ObiRopeCursor>();
            ropeData.Cursor.cursorMu = 0;
            ropeData.Cursor.direction = false;

            ropeData.ObiRope.tearingEnabled = _useTearing;
            if (_useTearing) {
                ropeData.ObiRope.tearResistanceMultiplier = _tearResistance;
            }

            ropeData.ObiRope.surfaceCollisions = _useSurfaceCollision;

            ropeData.ObiRope.stretchingScale = _stretchingScale;
            StartCoroutine(InitialiseRopeRoutine(ropeData, ropeInitialised));
        }

        IEnumerator InitialiseRopeRoutine(RopeData ropeData, Action ropeInitialised = null) {
            var localHit = Vector3.forward;

            // Procedurally generate the rope path (just a short segment, as we will extend it over time):
            int filterCollision = ObiUtils.MakeFilter(ObiUtils.CollideWithEverything, 0);
            int filterNoCollision = ObiUtils.MakeFilter(ObiUtils.CollideWithNothing, 0);

            ropeData.Blueprint.path.Clear();
            ropeData.Blueprint.path.AddControlPoint(Vector3.zero, Vector3.zero, Vector3.zero, Vector3.up, 1 / ropeParticleInverseMass, 0.1f, ropeThickness, filterCollision, Color.white,
                "Rope start");
            ropeData.Blueprint.path.AddControlPoint(localHit.normalized * 0.5f, Vector3.zero, Vector3.zero, Vector3.up, 1 / ropeParticleInverseMass, 0.1f, ropeThickness, filterCollision,
                Color.white, "Rope end");

            ropeData.Blueprint.path.FlushEvents();

            // Generate the particle representation of the rope (wait until it has finished):
            yield return ropeData.Blueprint.Generate();
            ropeData.IsInitialised = true;
            yield return null;
            ropeInitialised?.Invoke();
        }

        private void LayParticlesInStraightLine(Vector3 origin, Vector3 direction, ObiRope rope)
        {
            // placing all particles in a straight line, respecting rope length
            float length = 0;
            for (int i = 0; i < rope.elements.Count; ++i)
            {
                int p1 = rope.elements[i].particle1;
                int p2 = rope.elements[i].particle2;
                solver.prevPositions[p1] = solver.positions[p1] = origin + direction * length;
                length += rope.elements[i].restLength;
                solver.prevPositions[p2] = solver.positions[p2] = origin + direction * length;
            }
        }
       
        public void GenerateRope(RopeData ropeData, RopeControlPoint sourceRcp, RopeControlPoint endRcp, Action<RopeData> onRopeGenerated, bool generateImmediately) {
            StartCoroutine(GenerateRopeRoutine());

            IEnumerator GenerateRopeRoutine() {
                var endRcpPosition = endRcp.transform.position;
                yield return null;
                // Clear pin constraints:
                var pinConstraints = ropeData.ObiRope.GetConstraintsByType(Oni.ConstraintType.Pin) as ObiConstraints<ObiPinConstraintsBatch>;
                pinConstraints.Clear();

                if (generateImmediately) {
                    InitialiseRope(ropeData);
                }

                // Set the blueprint (this adds particles/constraints to the solver and starts simulating them).
                ropeData.ObiRope.ropeBlueprint = ropeData.Blueprint;
                ropeData.ObiRope.GetComponent<ObiRopeExtrudedRenderer>().enabled = true;

                // wait for the solver to load the rope, after the next physics step:
                yield return new WaitForFixedUpdate();
                yield return null;
                // set masses to zero, as we're going to override positions while we extend the rope:
                if (!generateImmediately) {
                    for (int i = 0; i < ropeData.ObiRope.activeParticleCount; ++i)
                        solver.invMasses[ropeData.ObiRope.solverIndices[i]] = 0;
                }

                float currentLength = 0;
                const float maxPercentOfDistance = 0.75f; // the max percent of the distance between the source and the hit that the rope can extend to in one frame
               
                //move definitions out of loop
                Vector3 origin;
                Vector3 direction;
               
                // while the last particle hasn't reached the hit, extend the rope:
                do {
                    //--Set Cursor and source to a set number of particles away from the end of the rope
                    SetCursorAndSourceMu(ropeData, cursorParticle, sourceParticle);

                    // calculate rope origin in solver space:
                    origin = solver.transform.InverseTransformPoint(sourceRcp.transform.position); //spawn from rope origin
                    // update direction and distance to hook point:
                    direction = endRcpPosition - origin;
                    float distance = direction.magnitude;
                    direction.Normalize();
                   
                    LayParticlesInStraightLine(origin, direction, ropeData.ObiRope);
                   
                    if (generateImmediately) {
                        ropeData.Cursor.ChangeLength(distance + extraRopeLengthOnSpawn);
                    }
                    else {
                        // calculate the max increment for this frame to stop the increment from being larger than the distance.
                        float maxIncrement = distance * maxPercentOfDistance;
                        var increment = ropeShootSpeed;

                        increment = Mathf.Min(maxIncrement, increment);
                        // increase length:
                        currentLength += increment;
                        // if we have reached the desired length, break the loop:
                        if (currentLength >= distance) {
                            ropeData.Cursor.ChangeLength(distance + extraRopeLengthOnSpawn);
                            break;
                        }

                        // change rope length (clamp to distance between rope origin and hook to avoid overshoot)
                        ropeData.Cursor.ChangeLength(Mathf.Min(distance, currentLength));
                    }
                    yield return null;
                } while (!generateImmediately);

                // wait for the last length change to take effect, and ensure the rope is straight:
                yield return new WaitForFixedUpdate();
                yield return null;
                LayParticlesInStraightLine(origin, direction, ropeData.ObiRope);
               
                // restore masses so that the simulation takes over now that the rope is in place:
                for (int i = 0; i < ropeData.ObiRope.activeParticleCount; ++i)
                    solver.invMasses[ropeData.ObiRope.solverIndices[i]] = ropeParticleInverseMass; // 1/0.1 = 10

                // Pin both ends of the rope (this enables two-way interaction between character and rope):
                var batch = new ObiPinConstraintsBatch();
                batch.AddConstraint(ropeData.ObiRope.elements[0].particle1, sourceRcp.ObiCollider, Vector3.zero, Quaternion.identity, 0, 1000, breakThreshhold);
                batch.AddConstraint(ropeData.ObiRope.elements[^1].particle2, endRcp.ObiCollider, Vector3.zero, Quaternion.identity, 0, 1000, breakThreshhold);
                batch.activeConstraintCount = 2;
                pinConstraints.AddBatch(batch);

                ropeData.ObiRope.SetConstraintsDirty(Oni.ConstraintType.Pin);

                //--Set Cursor and source to a set number of particles away from the end of the rope
                SetCursorAndSourceMu(ropeData, cursorParticle, sourceParticle);

                //Add Rope Data to both Control points
                endRcp.RopeActivated(ropeData);     // must happen before onRopeGenerated Electrics needs to know the RCPs Rope Data
                endRcp.InitialisePointOnRopeGenerated(ropeData);     // must happen before onRopeGenerated Electrics needs to know the RCPs Rope Data
                onRopeGenerated?.Invoke(ropeData); // calls hand wait finished, source.RopeActivated, RopeManager.RopeGenerated and RcpAttachPoint.AttachRcp
            }
        }
        public void SetCursorAndSourceMu(RopeData ropeData, float cursorParticlesFromEnd, float sourceParticlesFromEnd) {
            cursorParticlesFromEnd = Mathf.Clamp(cursorParticlesFromEnd, 2.0f, (float)ropeData.ObiRope.activeParticleCount - 2);
            sourceParticlesFromEnd = Mathf.Clamp(sourceParticlesFromEnd, 2.0f, (float)ropeData.ObiRope.activeParticleCount - 2);
            ropeData.Cursor.cursorMu = 1 - cursorParticlesFromEnd / ropeData.ObiRope.activeParticleCount;
            ropeData.Cursor.sourceMu = 1 - sourceParticlesFromEnd / ropeData.ObiRope.activeParticleCount;
        }
    }


Any advice or suggestions on how to resolve these issues would be greatly appreciated!
Thanks in advance!
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Messages In This Thread
Issues After Upgrading to Obi Rope 7: Bounciness, Jitter, and Rope Generation Problem - by Destro26 - 27-08-2024, 07:50 PM