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Frequently Asked Questions (FAQ)

Here are solutions to the most common questions encountered when simulating ropes and chains with Tensio.

⚛️ Physics & Simulation

Why is my rope vibrating or jittering?
  • Root Cause: Extremely low compliance (Compliance = 0.0) combined with few solver iterations (SubSteps < 6) or massive mass ratios can introduce numerical oscillation.
  • Resolution:
    1. Increase Sub Steps from 8 to 12 or 16 in Physics Settings.
    2. Add a microscopic amount of compliance (e.g. 0.0001) instead of absolute zero.
    3. Ensure that pinned GameObjects are updated during FixedUpdate() rather than Update().
My rope passes through objects without colliding. Why?
  • Root Cause: Fast movement (tunneling), insufficient particle radius, or layer mask exclusion.
  • Resolution:
    1. Verify the collider’s layer is checked in RopeController > Collision Mask.
    2. Slightly increase Particle Radius in Physics Settings.
    3. For critical obstacles (poles, characters, boxes), use Tensio’s Proxy Colliders (RopeBoxProxy, RopeCapsuleProxy), which are mathematically immune to tunneling.
How do I make the rope completely rigid like a steel rod or pipe?
  • Set Compliance to 0.0 and increase Sub Steps to 16.
  • Note that XPBD is specifically tuned for flexible dynamic bodies. For completely immovable steel bars, Unity’s standard Rigidbody joints or kinematic colliders may be more suitable.

⚡ Performance & Mobile

I have hundreds of ropes and framerates are dropping. What should I optimize?
  1. Enable Batching: Check Use Batching on all RopeRenderer and RopeChainRenderer components. This collapses hundreds of draw calls into single batches.
  2. Add RopeLODController: This provides the single highest performance gain by swapping distant 3D meshes for lightweight 2D billboard lines and suspending off-screen physics.
  3. Tune Particle Counts: Background cables typically look great with only 8 – 12 particles rather than 40.
Does Tensio work on Mobile (iOS / Android) and standalone VR (Quest)?
  • Yes. Because the core XPBD constraint solver is multi-threaded and compiled using Unity’s Burst Compiler, it runs with 0B GC allocation natively on ARM64 architectures.
  • Recommended mobile settings: Keep Particle Count between 15 – 25, use Proxy Colliders, and enable RopeLODController.

🎮 Gameplay & Interaction

Can I attach a rope to a moving character or Ragdoll?
  • Yes. Call rope.PinParticle(index, characterBoneTransform, contactPoint).
  • If the attached GameObject has a Rigidbody, Tensio automatically calculates reciprocal forces, allowing players to swing, climb, or pull attached objects.
How do I tether two separate objects together?
  • Pin index 0 to Object A using rope.PinParticle(0, objectA.transform, objectA.transform.position).
  • Pin index ParticleCount - 1 to Object B using rope.PinParticle(rope.ParticleCount - 1, objectB.transform, objectB.transform.position).
  • The rope will physically constrain the distance between both objects according to its resting length.

🎨 Visuals & Rendering

The rope texture appears stretched when winching. How do I fix it?
  • When changing rope length dynamically via code or RopeWinch, adjust the UV Offset property on RopeRenderer proportionally to simulate continuous sliding across pulleys.
Can I save or bake the dynamic rope mesh into a permanent asset?
  • Yes. Because RopeRenderer writes into a standard Unity Mesh, you can call AssetDatabase.CreateAsset(meshFilter.sharedMesh, "Assets/BakedRope.asset") in an editor script to save the resting posture as static scene geometry.