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How to make a knot? - zxinlong - 21-03-2018

Hi!
I am using Obi Rope to simulate a game of playing with a rope. The other conditions of the rope are satisfied, but the rope can easily pass through itself and cannot form a knot. I checked self collisions, but the effect is not obvious.
May I ask how to improve the self-collision effect or have other better ways to achieve it?

Thanks! Sonrisa

[Image: timg?image&quality=80&size=b9999_10000&s...gp%3D0.jpg]

The knot in the picture below is the effect I want：

[Image: 00D1EE24F72E86A5F4C486E1C10D4DB4.jpg-t.jpg]

RE: How to make a knot? - josemendez - 21-03-2018

(21-03-2018, 10:44 AM)zxinlong Wrote: Hi!
I am using Obi Rope to simulate a game of playing with a rope. The other conditions of the rope are satisfied, but the rope can easily pass through itself and cannot form a knot. I checked self collisions, but the effect is not obvious.
May I ask how to improve the self-collision effect or have other better ways to achieve it?

Thanks! Sonrisa

[Image: timg?image&quality=80&size=b9999_10000&s...gp%3D0.jpg]

The knot in the picture below is the effect I want：

[Image: 00D1EE24F72E86A5F4C486E1C10D4DB4.jpg-t.jpg]

Hi there!

I highly doubt doing this in realtime is even possible. The sheer collision resolution and amount of iterations needed to robustly support this use case is way too high. By cranking up rope resolution (ObiRope->resolution->Initialize), distance and particle collision constraint iteration count (ObiSolver) and by reducing the physics timestep (ProjectSettings->Time->fixed timestep), you will be able to make a few knots under little tension.

However increasing rope tension over a certain threshold (higher the more time you spend solving physics) will undo any knots in the rope.

cheers,

RE: How to make a knot? - zxinlong - 22-03-2018

(21-03-2018, 05:10 PM)josemendez Wrote: Hi there!

I highly doubt doing this in realtime is even possible. The sheer collision resolution and amount of iterations needed to robustly support this use case is way too high. By cranking up rope resolution (ObiRope->resolution->Initialize), distance and particle collision constraint iteration count (ObiSolver) and by reducing the physics timestep (ProjectSettings->Time->fixed timestep), you will be able to make a few knots under little tension.

However increasing rope tension over a certain threshold (higher the more time you spend solving physics) will undo any knots in the rope.

cheers,

Hi, Jose!Thanks for helping me.

I successfully made a knot according to your method, but now I have some new problems:
1. There is a large gap in the knot, resulting in the rope cannot be close together;
2. The rope has been shaking and cannot stop.
Is there any way to make the rope itself close together quietly? Sonrisa

[attachment=108]
[attachment=109]