Question about a specific Obi Rope application

[josemendez]

Hello I want to create a rather long hose dragged by a dynamic object throughout the scene, while keeping collision with the scene objects like building, trees etc. as well as realistic hose baviour, including two-way dragging. Is Obi Rope suitable for such application? Thanks in advance for help.

Hi there!

Obi does support two-way rigidbody coupling (dragging), collision with dynamic and static objects, etc.
Whether or not it would fit your use case basically depends on your hose length to width ratio, and how accurate you need collision detection to be.

Let me explain: the longer and thinner the rope, the larger the amount of particles Obi will need to represent it, and the larger the amount of constraint iterations you´ll need to keep it from stretching.

If you need accurate collision detection with objects that are as thin or thinner than the rope, this also poses problems, since they can slip trough gaps in the particle representation of the rope.

All of these issues can be resolved by brute force: increase the amount of solver iterations until the behavior is acceptable. But of course, more iterations = less performance. So it all depends on these three things:

- Precision requisites of your collision detection. Objects thicker than the rope diameter will collide ok, smaller objects will not.
- Length to width ratio of the rope/hose. A ratio of 50:1 is ok, a ratio of 2000:1 is not.
- Whether your performance budget is enough to get it all working as needed. For a single rope on desktop platforms it's fairly unlikely you'll have performance problems, but still.