12-03-2021, 11:07 AM
(This post was last modified: 12-03-2021, 11:09 AM by josemendez.)
Hi Giuseppe,
For a stiff-as-possible rope, stretching scale should be 1 (100%), and stretching compliance (compliance = elasticity) should be 0.
Changing the number of substeps does not affect the number of particles in the rope, but the precision of the simulation. More substeps will yield stiffer rope. Also, make sure the SOR factor for distance constraints is 1 (100%). This controls the weight of the constraints in the simulation, so if the value is lower than 1 distance constraints won't be fully enforced resulting in stretchy rope.
Adding particles to the rope won't make it more stiff, but the opposite. If anything, you should reduce rope resolution.
The mass ratio between the rope and the rigidbody also greatly affects the convergence of the simulation (and as a result, the stiffness of the rope). If the rigidbody is much heavier than the rope, the rope will have a hard time supporting it. This behavior is common to all physics engines, not just Obi. If the rigidbody is very heavy, reduce its mass or increase the rope's mass.
You can see the "Crane" or "FreightLift" sample scenes for examples of rigidbodies hanging from ropes.
Let me know how it goes!
Quote:Even if I have changed the stretching scale and stretch compliance the rope is still too much stretchy and will stretch until the object falls on the floor.
For a stiff-as-possible rope, stretching scale should be 1 (100%), and stretching compliance (compliance = elasticity) should be 0.
Quote:I also changed the number of substeps in the Obi Fixed Updater in order to add particles to my rope and make it more stiff, but nothing seems to work.
Changing the number of substeps does not affect the number of particles in the rope, but the precision of the simulation. More substeps will yield stiffer rope. Also, make sure the SOR factor for distance constraints is 1 (100%). This controls the weight of the constraints in the simulation, so if the value is lower than 1 distance constraints won't be fully enforced resulting in stretchy rope.
Adding particles to the rope won't make it more stiff, but the opposite. If anything, you should reduce rope resolution.
The mass ratio between the rope and the rigidbody also greatly affects the convergence of the simulation (and as a result, the stiffness of the rope). If the rigidbody is much heavier than the rope, the rope will have a hard time supporting it. This behavior is common to all physics engines, not just Obi. If the rigidbody is very heavy, reduce its mass or increase the rope's mass.
You can see the "Crane" or "FreightLift" sample scenes for examples of rigidbodies hanging from ropes.
Let me know how it goes!