Obi Official Forum › Obi Users Category › Obi Cloth v
Help  Link two Obi objects with Rope

Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Thread Modes
Help  Link two Obi objects with Rope
matchalover Offline
General User
Posts: 16
Threads: 9
Joined: Jul 2017
Reputation: 0
#1
10-03-2018, 03:35 PM
I want to make a link between two Obi objects with rope but when i pull the rope to the left, the rope seems to jump out of the Obi Cloth. I need some help !
Here is an example: https://www.youtube.com/watch?v=hlK-j3rf...e=youtu.be
Find
Reply
josemendez Offline
Forum Admin
*******
Posts: 5,901
Threads: 22
Joined: Jun 2017
Reputation: 366
Obi Owner:
  • Rope
  • Cloth
  • Fluid
#2
10-03-2018, 07:29 PM
(10-03-2018, 03:35 PM)matchalover Wrote: I want to make a link between two Obi objects with rope but when i pull the rope to the left, the rope seems to jump out of the Obi Cloth. I need some help !
Here is an example: https://www.youtube.com/watch?v=hlK-j3rf...e=youtu.be

Hi!

I don't really understand what you're trying to accomplish... in the video I can see a rope that you force trough a collider, then when you pull it slightly to one side it of course slips out of it due to collision detection, hitting the cloth sphere next to it.

What is the behavior you'd expect in this case?

cheers,
Website Find
Reply
matchalover Offline
General User
Posts: 16
Threads: 9
Joined: Jul 2017
Reputation: 0
#3
10-03-2018, 07:41 PM
(10-03-2018, 07:29 PM)josemendez Wrote: Hi!

I don't really understand what you're trying to accomplish... in the video I can see a rope that you force trough a collider, then when you pull it slightly to one side it of course slips out of it due to collision detection, hitting the cloth sphere next to it.

What is the behavior you'd expect in this case?

cheers,
I don't want the rope to slips out of the sphere. I want to simulate like the video in this link, with ObiCloth for the pink thing and ObiRope for the rope. Can you give any suggestion?
https://vimeo.com/96087404
Find
Reply
josemendez Offline
Forum Admin
*******
Posts: 5,901
Threads: 22
Joined: Jun 2017
Reputation: 366
Obi Owner:
  • Rope
  • Cloth
  • Fluid
#4
10-03-2018, 08:34 PM (This post was last modified: 10-03-2018, 08:48 PM by josemendez.)
(10-03-2018, 07:41 PM)matchalover Wrote: I don't want the rope to slips out of the sphere. I want to simulate like the video in this link, with ObiCloth for the pink thing and ObiRope for the rope. Can you give any suggestion?
https://vimeo.com/96087404

Hi there,

This is not possible to achieve with ObiRope or ObiCloth, at least not with the functionality provided out of the box.

There's nothing that prevents a rope to exit a solid collider, in fact quite the opposite: collision constraints are designed to ensure rope particles stay outside of colliders when possible. Simply moving the rope trough a sphere will not automagically sew trough it.

What you're looking for (suture simulation) should be implemented as a position -or velocity- constraint. You should look into how is this implemented in surgical simulators, then write your own code to implement this functionality. However it will be a pretty daunting task if you're not used to physics programming.

Here's some papers to get you started. The first paper contains math for sliding point and sliding direction constraints, which are used to implement the sutures. You can use these equations to work out the forces you need to apply to the rope particles in order to satisfy the constraints:

https://pdfs.semanticscholar.org/d390/33...71df6c.pdf
https://pdfs.semanticscholar.org/b4b5/75...dd4c0f.pdf

kind regards,
Website Find
Reply