Help hi, should I use obi rope for this type grappling system?

[usemahrope88]

hello, thank you dev for your hard work, i own this asset and want to ask if remaking this style of grappling system is feasible/do-able making use of obi-rope?:



(huh? now that i look closely on second video, maybe this game already was using obirope?)

i was also looking at your other asset:

https://assetstore.unity.com/packages/to...tor-133620

is it better instead?

feature set i am looking at implementing:

1. dynamic stretch and reposition, with anchor (i guess this is removal and addition of active particles within chain??)

2. continuous collisions for arbitrary collision surfaces(tree, boat, box, character, bush, anything) with anchor (supporting wrapping and two points contact) (also operates while player moves about without going through terrain)

3. momentum/add force reactive (permit swinging, i guess i can apply force to mid point of rope and also end in intervals based on player input(maybe determine axis based on controller z, x, y, facing) and maximal incremented multiplier over a set predetermined limit, ex: mid/end point+0.1force, time step, +0.2, +0.3, +0.4 (not sure how to solve this yet)


uhh guess its easier than i thought, seems to already do most, im wondering though if using your asset (no source code for obirope) will be good for lifetime of a project like this? i wouldnt need source code in the future if i simply make use of rope property? 

i could implement a simplistic solution myself but i just want to save time but dont want to be stuck later. but then again i can just use your system for certain parts of my grappling system and then add on custom code for specific use, not a issue either way just curious (also i have no time to edit source code anyway just like having the option to extend functionality and make use of api, not really modify just addition libs)

i think your asset is the fastest for this yes??
thank you again for hard work on this great job, i am also considering to get obi cloth but i will wait and see if i can use it (for dynamic flags)

[josemendez]

hello, thank you dev for your hard work, i own this asset and want to ask if remaking this style of grappling system is feasible/do-able making use of obi-rope?:

Can't tell for sure, but in the video the rope does not seem to collide with anything (not even the big chunky rocks), and doesn't  move/vibrate at all when under tension, so my guess is this just a simple spring joint. It's the fastest/simplest/most robust way of implementing a grapple hook, and the way most games do it unless you need fancy stuff.

i was also looking at your other asset:

https://assetstore.unity.com/packages/to...tor-133620

is it better instead?

Filo does not support collision detection with arbitrary objects (just a predefined list of objects that can't change at runtime), does not support self- or inter- collisions, does not model torsion, only supports 100% tense cables.... it's considerably simpler than Obi and does a much better job simulating complex pulley/winch systems, but it does have a fair share of limitations. So it depends on what your requirements are.

feature set i am looking at implementing:

1. dynamic stretch and reposition, with anchor (i guess this is removal and addition of active particles within chain??)

By "Dynamic stretch" you mean changing the rope's rest length? That can be done using cursors:
http://obi.virtualmethodstudio.com/manua...ursor.html

See the included GrapplingHook sample scene for a simple example of a grappling hook using cursors and pin constraints.

2. continuous collisions for arbitrary collision surfaces(tree, boat, box, character, bush, anything) with anchor (supporting wrapping and two points contact) (also operates while player moves about without going through terrain)

Can only be done with Obi. Tbh I know of no other rope system in any engine that does this.

3. momentum/add force reactive (permit swinging, i guess i can apply force to mid point of rope and also end in intervals based on player input(maybe determine axis based on controller z, x, y, facing) and maximal incremented multiplier over a set predetermined limit, ex: mid/end point+0.1force, time step, +0.2, +0.3, +0.4 (not sure how to solve this yet)

You can add forces to any particle in the rope, however swinging is usually implemented by adding a force to the character itself. Adding forces mid-rope is not too realistic for a grappling hook.

uhh guess its easier than i thought, seems to already do most, im wondering though if using your asset (no source code for obirope) will be good for lifetime of a project like this? i wouldnt need source code in the future if i simply make use of rope property? 

Full source code is included. Editor tools, util scripts, core physics engine, everything. Only the fallback backend (Oni) source isn't included because it's a native library, but using it isn't recommended anyway. You should be using Burst, which is the default. See our FAQ:
http://obi.virtualmethodstudio.com/faq.html

Is the core physics library source code included?

The full C# source code for the Burst backend is included. The source code for the Oni backend is not. Oni is written in highly portable C++14. We do license it on a per-case basis, so contact us if you're interested.
Sources for everything else (C# MonoBehaviours, classes, shaders, etc.) are included.

i could implement a simplistic solution myself but i just want to save time but dont want to be stuck later. but then again i can just use your system for certain parts of my grappling system and then add on custom code for specific use, not a issue either way just curious (also i have no time to edit source code anyway just like having the option to extend functionality and make use of api, not really modify just addition libs)

i think your asset is the fastest for this yes??

Without a shadow of doubt .

Let me know if you need any help. cheers!

[usemahrope88]

thanks!

the video i talk about was this one




when i look closely the rope material looks similar to your default one, so i was just wondering

anyway enough of that time for me to go to work implementing experimental models and tests i will make new post if i get stuck on something

thanks again!!

[josemendez]

Hi!

The material is a rather common rope texture. However physics-wise this looks just like a simple distance/spring joint between the character and the hook. The rope itself has no physics whatsoever in any of the videos, it's always just a straight line (no vibration/jiggling, no bending, no collisions with anything else)

[usemahrope88]

Hi!

The material is a rather common rope texture. However physics-wise this looks just like a simple distance/spring joint between the character and the hook. The rope itself has no physics whatsoever in any of the videos, it's always just a straight line (no vibration/jiggling, no bending, no collisions with anything else)

ok it took me forever since i have played the game myself to find an example of what i am aiming to achieve (time stamp- 2:15-2:28 ):



you can see at 2:16ish the collisions, i could not find one demonstrating rope to tree collisions, but it was similar, there was also enable collision from a point, around a terrain or edge of cliff or platform, to the anchor and character as similarly done in this video but it seem to be a sharp bend, is this done using ray tracing which make new anchor point in chain or something?

[josemendez]

Yes, this looks like it raytraces to find a new anchor point. This is how the classic ninja rope in the Worms series was done, how Umihara Kawase does it, also how ZenBound does it... and is a bit of a step up from a simple spring. Still no physics involved (no friction forces, no cable slack, no vibration modes, etc).  Has the advantage that it's extremely cheap compared to actual simulation, which is what Obi does.

The basic algorithm is covered here:
https://www.reddit.com/r/Unity2D/comment..._mechanic/

[usemahrope88]

Yes, this looks like it raytraces to find a new anchor point. This is how the classic ninja rope in the Worms series was done, how Umihara Kawase does it, also how ZenBound does it... and is a bit of a step up from a simple spring. Still no physics involved (no friction forces, no cable slack, no vibration modes, etc).  Has the advantage that it's extremely cheap compared to actual simulation, which is what Obi does.

The basic algorithm is covered here:
https://www.reddit.com/r/Unity2D/comment..._mechanic/

thank you for your help, i will research this more, with your asset i should be able to figure some stuff out, i will keep you posted of my results if i make something worth showing