Hi! I'm new to Obi Rope and just wanted to say—it's a fantastic asset. I really appreciate the craftsmanship behind it.
I think I'm running into a user error and could use some help troubleshooting. I’ve attached three images below, in addition, here is a link to a video of the problem.
Each of the plugs in my setup are Obi Rigidbodies connected to the rope using dynamic attachments. I believe I’ve set up the constraints correctly for my use case, and I’ve experimented with different iteration and substep values.
I’ve also tested different mass settings—for example, setting the rope and rigidbodies both to 0.1, or the rope at 0.1 and the rigidbodies at 1.0, and vice versa—but the issue still occurs.
Here’s what I’m hoping to figure out:
Is there a way to prevent these gaps from forming when the rope is pulled forcefully?
If the gaps are unavoidable due to physics constraints, is there a way to reset the rope when it’s stretched beyond a certain threshold?
Ultimately, I’m trying to simulate a stiff, non-stretchable wire. Ideally, users shouldn’t be able to stretch it at all or see any slack.
I'm not really sure where to even start debugging this as there's no issue in the editor (or the editor just handles it less strictly, but no error that I've seen). It doesn't happen 100% of the time either, but sometimes when testing a build as soon as the scene with the obi rope loads the whole application crashes with this stack trace:
It's not from one specific rope either, it happens seemingly randomly with any rope implementation anywhere in the game. This only started happening after upgrading from Obi 6 to Obi 7.0.5. I followed the upgrade guide with re-generating the blueprints, etc. We're using the Burst back-end for the ropes as we need collisions on the ropes and I couldn't figure out if there was a way to make that work with the GPU-based backend, so I haven't tested the GPU one in a build.
Any idea what could be causing this or how I could debug further?
Is there a way to enable interactions with a unity particle system and Obi Soft body?...i suspect not
I seem to suspect it shoudl be possible with an OBI partilce system....but i cant seem to find out how to create an Obi Particle emitter... ( i have Obi soft body and Cloth)
essentially i want to simulate a ( bio science) cell being targetted by a swarm of rigid body spheres.
Hey there, I've recently been updating my project from Obi 6 to 7, and also switching to use the GPU compute solver. I noticed in the editor after some testing and re-starting play mode, it would pop up 12 warnings with this:
Code:
GarbageCollector disposing of GraphicsBuffer. Please use GraphicsBuffer.Release() or .Dispose() to manually release the buffer.
This wasn't a major issue, however I also started to get crashes on the built version of my game when exiting, with the stack trace in the Player.log ending with:
Doing a build with the Development Build flag did not crash on exit but also threw those GarbageCollector warnings.
After some tracing, all of the warnings were coming from ComputeColliderWorld.cs. I added Dispose()s for each of the buffers that were causing problems to the OnDestroy:
This fixed the warnings popping up in editor, and the game no longer crashes on exit in the built version. There may be other buffers that also need to be disposed in this component but these were the ones that were causing issues for my game. Just wanted to let you know about this problem.
1,2,3 are attachment on the rope.
I'm trying to extend or rewind the rope at these two position
3--2>-----<1 where > < can be < > (cursor direction), meaning rope can extend from the two points or rewind from the two.
It works fine with the one next to 1 (the start of the rope, cursor is at 0, source at .5
But if I try to place the cursor next to the 2, something like cursor at .3 and source still at .5 it behave differently, no particle are added to the rope at this position.
Is there something I should know about cursor and attachments?
Edit: IF I understand correctly one of the issue is, when the cursor is at .75 and the rope is getting bigger, the cursor move, so I need to find a way to dynamically set it to one particle...
Thanks a lot,
Hello,
I managed to save and reload particle positions in ObiRope v6.x using code under the Copy ropes in play mode thread. However, this no longer works in ObiRope v7.x. Could you help me identify what I might be missing?
Here’s my current code:
Code:
public void Load(Vector3[] particlePositions, Vector3 lastParticlePosition)
{
int particleCount = particlePositions.Length;
while (rope.activeParticleCount > particleCount)
{
rope.elements.RemoveAt(rope.elements.Count - 1);
rope.DeactivateParticle(rope.activeParticleCount - 1);
}
while (rope.activeParticleCount < particleCount)
{
rope.elements.Add(new ObiStructuralElement
{
particle1 = rope.elements[^1].particle1,
//maybe this should be so:
//particle2 = rope.elements[^1].particle2,
particle2 = rope.solverIndices[rope.activeParticleCount],
restLength = rope.interParticleDistance
});
rope.CopyParticle(rope.activeParticleCount - 1, rope.activeParticleCount);
rope.ActivateParticle(); // This doesn't have an actorIndex anymore.
}
I am working with attachments for the first time using Obi Fluid. I am able to create the attachment with a proper target and particle group, but when adding particles to the particle group, nothing happens.
Additionally, if I try to disable/reenable the attachment at runtime (which I don't even think is necessary if I'm just adding/removing particles), then unity crashes and gives the GPU error "Failed to present D3D11 swapchain due to device reset/removed". I am using compute backend.
Code:
void Solver_OnCollision (ObiSolver solver, ObiNativeContactList contacts){
for(int i = 0; i < contacts.count ; ++i)
{
//Get properies of the particle in the contact
int particleIndex = solver.simplices[contacts[i].bodyA];
ObiSolver.ParticleInActor pa = solver.particleToActor[particleIndex];
ObiParticleAttachment attachment = pa.actor.gameObject.GetComponent<ObiParticleAttachment>();
ObiParticleGroup group = attachment.particleGroup;
//Changing the collision index of the particle so that it won't collide anymore
//In preparation for attaching to object
solver.filters[particleIndex]=ObiUtils.MakeFilter(ObiUtils.CollideWithEverything, (1 << 1));
//Add particle to attachment group between emitter and object
if(!group.ContainsParticle(pa.indexInActor)){
group.particleIndices.Add(pa.indexInActor);
attachment.particleGroup=group;
Debug.Log("Attachments count " + attachment.particleGroup.Count);
}
}
}
Do I understand correctly from documentation that only cloth has simulation of aerodynamics from particle velocity?
Is there a way to enable this, or do I need to do this by code or apply fake "wind" each tick? E.g. apply aerodynamics on bones for ears when moving a character.
Is it possible to have the root bone be part of the chain as if there was a parent transform with same position and rotation with "Fix Root" enabled?
I feel this should be a opt in to have the root bone be driven by animation or fully simualted. It is not great for workflow to have to modify existing rigs to enable this behaviour.
Hi, I've been heavily using Obi (cloth and rope) for several years now in the development of Following Seas. I'm quite happy with it overall, with really the biggest issue coming down to performance. Typically about 30-50% of total profiler load goes into the system -- which has been acceptable, but definitely reduces the number of runnable systems for users.
I've been looking into Obi 7, as performance seems to be a major focus, and have also split into a separate project branch to test it out -- but have a couple questions if you don't mind.
I'm struggling with the removal of Proxies -- are there any plans for a similar system, or revisions to the decimation? I like the automatic decimation, but I find that there isn't near the control that was available with proxies. For example, my cloth meshes rely on specific groups for attachment points, like the rays of a battened sail, or the corners where ropes would attach. Decimation on my more detailed meshes often causes these points to be far off from where they should be, or causes topology lines to become very wobbly due to merging inconsistently up and down when parallel lines of vertices are present. It would be nice to exclude vertex groups from decimation, or have a method of ensuring the shape of the mesh isn't overly affected.
I didn't see any method for controlling this, do you have any suggestions?
Secondly, it seems that ambient force zones have been removed -- is it preferred to have a wind force zone follow affected objects around, or to set wind directly through the solver?
I've attached a beautifully rendered version of my struggle with blueprints. The left indicates the result gained via the Obi 6 method, with the red dots representing vertices on the simplified mesh. The central black line is a group used for particle attachment, and the red corner is a point were a rope would attach.
On the right is a somewhat dramatized example of what I'm encountering through decimation.
