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Bug / Crash Unstable rope only when interpolating in build - Printable Version

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+--- Thread: Bug / Crash Unstable rope only when interpolating in build (/thread-2732.html)

Unstable rope only when interpolating in build - cfinger - 01-02-2021

First, thanks for the great asset! After building my own rope using joints, I am impressed with the behavior and performance of obi rope.

I'm currently having an issue where the rope behaves as expected in the editor but on play mode it isn't stable and flies everywhere. 

Set up: 
  • Rope with 2 attachments, one static, one dynamic.
  • Attachments are outside of colliders, and both control points are the same phase as the nearest collider
  • Using Burst
  • Obi Solver has interpolate selected 
When I make a build, the rope will fly everywhere, despite the attachments behaving as expected. If I turn off interpolation, the rope looks fine, despite a ton of visual jitter (the static attachment is on a moving rigidbody). 

I would really prefer to use interpolate to avoid this jitter. Any ideas? 

Thank you.

RE: Unstable rope only when interpolating in build - josemendez - 02-02-2021

Hi there,

I’m unable to reproduce this behavior, using a setup similar to the one you describe. Interpolation is only a post-process of the particle positions that the simulation outputs, it should not affect the simulation itself in any way as interpolated positions are just discarded at the end of each frame (not used as input for the next frame’s simulation)

Also, interpolation is intended to eliminate stutter (stop-motion like effects) when using large fixed timesteps. It basically interpolates particle positions from one physics update to the next. “jitter” as in "erratic movement" should not happen regardless of using interpolation or not.

Can you share a short video of the issue, or a repro project/scene?

kind regards,