18-06-2026, 08:00 AM
(This post was last modified: 18-06-2026, 10:33 PM by josemendez.)
Hi!
The color mixing to match the totem's color is a nice mechanic, well designed!
There is, one of the example scenes (TangledRopes) has a component that does exactly this: ObiRopeReel. It strives to keep the tension of the rope inside a specific range, reeling it in if it's too loose and reeling it out if it's too tense.
Not sure what you mean by "around the 0-coordinate". Collisions are calculated in solver space -like everything else in Obi- in a pretty traditional way as far as physics engines work: the pipeline is split into a broad phase and a narrow phase.
In the broad phase, the engine calculates a bounding box for every simplex (simplex = particle if you're not using surface collisions, simplex = segment between two particles if you are), then it checks which pairs of bounding boxes overlap.
In the narrow phase: for those simplex pairs whose aabbs overlap, it calculates the positional corrections needed to keep them from penetrating into each other.
Not sure what you mean about this either: there's no way to turn off collisions for a rope. Either you turn off collisions solver-wide, or you exclude specific pairs of particles from colliding with each other using collision filters.
Maybe you’re referring to the “surface collisions” checkbox on the rope? That doesn’t deactivate collisions, it enables/disables using the entire surface of the rope for collisions instead of just the particles. Explained here: https://obi.virtualmethodstudio.com/manu...sions.html
Let me know if I can be of any help!
The color mixing to match the totem's color is a nice mechanic, well designed!
(17-06-2026, 06:02 PM)vendolis Wrote: It was a fun experiences esp to keep the rope steady and under tension, while not over stretching it. I kind of wish there was a "tensioner" for the rope that keeps the rope at a specific tension all the time.
There is, one of the example scenes (TangledRopes) has a component that does exactly this: ObiRopeReel. It strives to keep the tension of the rope inside a specific range, reeling it in if it's too loose and reeling it out if it's too tense.
(17-06-2026, 06:02 PM)vendolis Wrote: I also wished there was more documentation on how the rope collisions are calculated, since apparently they are done around the 0-coordiantes and you can collide with them,
Not sure what you mean by "around the 0-coordinate". Collisions are calculated in solver space -like everything else in Obi- in a pretty traditional way as far as physics engines work: the pipeline is split into a broad phase and a narrow phase.
In the broad phase, the engine calculates a bounding box for every simplex (simplex = particle if you're not using surface collisions, simplex = segment between two particles if you are), then it checks which pairs of bounding boxes overlap.
In the narrow phase: for those simplex pairs whose aabbs overlap, it calculates the positional corrections needed to keep them from penetrating into each other.
(17-06-2026, 06:02 PM)vendolis Wrote: even though collisions are turned off for the rope.
Not sure what you mean about this either: there's no way to turn off collisions for a rope. Either you turn off collisions solver-wide, or you exclude specific pairs of particles from colliding with each other using collision filters.
Maybe you’re referring to the “surface collisions” checkbox on the rope? That doesn’t deactivate collisions, it enables/disables using the entire surface of the rope for collisions instead of just the particles. Explained here: https://obi.virtualmethodstudio.com/manu...sions.html
Let me know if I can be of any help!