How to give a tension to rope...

[sangku2000]

Hi!
I wanna give a rope tense.

No longer give a length to rope

but when i move a rope's X transform, it getting more longger.....

What can i do...?

---

this is now. no tension, and draw is my expectaition.

[josemendez]

Tension is defined as a force that increases strain. Strain is the ratio between the rope's rest length and its current length:

Code:

float strain = rope.restLength / rope.CalculateLength();

So if you want to increase strain, all you need to do is reduce the rope's rest length so that it is a percentage of the length between the points it is attached to. You can use a cursor to do that, like this:

Code:

cursor.ChangeLength(Vector3.Distance(attachmentA, attachmentB) * 0.6f); //rope is 40% shorter than the distance between its endpoints.

See: http://obi.virtualmethodstudio.com/manua...ursor.html

[sangku2000]

It not changing a component but a code?

And than, what script?

I've searched all scripts using a keyword "cursor.ChangeLength" but, i only found ObiRopeCursor.cs ....

is it correct to change this cs file??

[josemendez]

It not changing a component but a code?

Yes, you need to write some code for this to work.

And than, what script?

Your own script, you need to write a script that calls cursor.ChangeLength(yourNewLength), where "cursor" is a variable of type ObiCursor.

I've searched all scripts using a keyword "cursor.ChangeLength" but, i only found ObiRopeCursor.cs ....is it correct to change this cs file??

Im a bit confused by this question...you don't have to change ObiRopeCursor.cs or any other Obi script, if you do you can break the asset.

ChangeLength() is a public method exposed by ObiRopeCursor. You simply add a ObiRopeCursor component to your rope, and then call its ChangeLength() method in your own script. Take a look at the manual for an in-depth explanation and some sample code:
http://obi.virtualmethodstudio.com/manua...ursor.html

Note C# scripting skills are an absolute requirement to be able to use Obi, if you're unfamiliar with scripting/programming you'll find it very hard to use. See our FAQ:
http://obi.virtualmethodstudio.com/faq.html

Is scripting / coding required to use Obi?

For anything except the bare basics, yes. Obi is written in HPCS (high performance C#) and C++11, and it exposes a C# API. Obi deals with hundreds of particles and thousands of constraints every frame. These are exposed to you, the user, so learning how to write performant code is a prerequisite.

[sangku2000]

Thanks for your advise! It perfectly work!

↓ this is my code!
public class RopeStrain : MonoBehaviour
{
    ObiRopeCursor cursor;
    ObiRope rope;

    public Transform attachmentStart;
    public Transform attachmentEnd;

    public float distanceRate = 0.45f;

    // Start is called before the first frame update
    void Start()
    {
        rope = GetComponent<ObiRope>();
        cursor = GetComponent<ObiRopeCursor>();
    }

    // Update is called once per frame
    void LateUpdate()
    {
        AdjustStrain();
    }

    private void AdjustStrain()
    {
        if (attachmentStart == null || attachmentEnd == null)
        {
#if UNITY_EDITOR
            Debug.Log("transform null...!!!");
#endif
            return;
        }
        cursor.ChangeLength(Vector3.Distance(attachmentStart.transform.position, attachmentEnd.transform.position) * distanceRate * Time.deltaTime);
   // length is adjusted by rate and time.
}

But.... I think self collider is seem to be not working...

I think i need to recalculate the element.. is right?

[josemendez]

        cursor.ChangeLength(Vector3.Distance(attachmentStart.transform.position, attachmentEnd.transform.position) * distanceRate * Time.deltaTime);
   // length is adjusted by rate and time.
}

But.... I think self collider is seem to be not working...

Do not multiply by Time.deltaTime, it does not make any sense in this context. You're not changing the length over time, you're just setting it to a specific value. Multiplying by Time.deltaTime (which is a very, very small value, like 0.001) will set the length of your rope to be pretty much zero. This will result in a rope made of only two particles: one at each end. So no collisions will take place since there are no particles to collide with.

I think i need to recalculate the element.. is right?

No need to

[sangku2000]

cursor.ChangeLength(Vector3.Distance(attachmentStart.transform.position, attachmentEnd.transform.position) * distanceRate);    // rope adjust by rate.

↑↑↑↑↑ This is new code...! (distanceRate is almost 0.1f)

But collider is not works now. Because of no particle impacted. (you've said)

I wanna make when ropes contact, they become a tangle. (now ropes doesn't impact each other)

In this situation, I need to recalculate rope's particles or make own particles??

I think i torture you....

Sorry... very very sorry....

[josemendez]

cursor.ChangeLength(Vector3.Distance(attachmentStart.transform.position, attachmentEnd.transform.position) * distanceRate);    // rope adjust by rate.

↑↑↑↑↑ This is new code...! (distanceRate is almost 0.1f)

But collider is not works now. Because of no particle impacted. (you've said)

I wanna make when ropes contact, they become a tangle. (now ropes doesn't impact each other)

Add a ObiParticleRenderer component to your rope, make sure there's particles all along the rope. See:
http://obi.virtualmethodstudio.com/manua...ering.html

Assuming the rope does contain enough particles and there's no large gaps in between them, there's other issues that can prevent accurate collision detection:

- Make sure particle collision constraints are enabled in the solver: http://obi.virtualmethodstudio.com/manua...olver.html
- Make sure collision filters are properly set up. By default, ropes collide with everything, so unless you've changed this or you've reused a blueprint that had incorrect filter settings, it should work fine. For info on collision filters, see:http://obi.virtualmethodstudio.com/manual/6.2/collisions.html
- If your ropes are very tense, then gaps can appear in between particles, allowing ropes to pass trough each other. Using surface collisions can improve this. See: http://obi.virtualmethodstudio.com/manua...sions.html

You mention your distanceRate variable is 0.1, that will make the rope 10% of the distance between its ends and will likely open huge gaps in between particles. I don't think you need such large tension, any real-world rope or chain would snap under such strain. distanceRate is meant to be set to 0.8-0.99, or some value close to 1.

In this situation, I need to recalculate rope's particles or make own particles??

No need to. Ropes will readily collide with each other, as long as they're correctly setup.

Sorry... very very sorry....

No worries! answering questions is what I'm here for