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Rope used for Crane - flamingo - 10-04-2019

Hello everyone Sonrisa
I am using Obi Rope for a crane simulation. However the rope doesn't react the way I want it to. I am using the lowest amount of particles which is 2. However we make it so we adjust the rope length, and every time I change the length, it adds particles and it looses the stiffness which makes the crane act weirdly because of the rope. Is there anyway I can make it so, it doesn't add more particles when I change the rope length via code? The attachment shows the way I have my ropes. and it's parameters.


RE: Rope used for Crane - josemendez - 10-04-2019

(10-04-2019, 01:36 PM)flamingo Wrote: Hello everyone Sonrisa
I am using Obi Rope for a crane simulation. However the rope doesn't react the way I want it to. I am using the lowest amount of particles which is 2. However we make it so we adjust the rope length, and every time I change the length, it adds particles and it looses the stiffness which makes the crane act weirdly because of the rope. Is there anyway I can make it so, it doesn't add more particles when I change the rope length via code? The attachment shows the way I have my ropes. and it's parameters.

Hi,

Why not changing the constraint length directly? The ObiRopeCursor component will automatically add particles at fixed intervals to keep sane mass sampling. However you can simply set the length of the distance constraint between both particles, no need to use the cursor. See:
http://obi.virtualmethodstudio.com/tutorials/scriptingconstraints.html

Also, why use a particle simulator, then avoid using particles? Take a look at our Filo simulator, which is specifically designed to simulate cranes and cable-driven machinery (long ropes, huge mass ratios). I think it is a much better match for your use case. In case you think the same, we can swap a Filo license for your Obi one:
https://assetstore.unity.com/packages/tools/physics/filo-the-cable-simulator-133620


RE: Rope used for Crane - flamingo - 15-04-2019

(10-04-2019, 03:31 PM)josemendez Wrote: Hi,

Why not changing the constraint length directly? The ObiRopeCursor component will automatically add particles at fixed intervals to keep sane mass sampling. However you can simply set the length of the distance constraint between both particles, no need to use the cursor. See:
http://obi.virtualmethodstudio.com/tutorials/scriptingconstraints.html

Also, why use a particle simulator, then avoid using particles? Take a look at our Filo simulator, which is specifically designed to simulate cranes and cable-driven machinery (long ropes, huge mass ratios). I think it is a much better match for your use case. In case you think the same, we can swap a Filo license for your Obi one:
https://assetstore.unity.com/packages/tools/physics/filo-the-cable-simulator-133620

Hi There,
We Already have tried using your other asset Filo Simulator, however, because we cant add colliders to the rope, it goes through the crane itself and also the pulley it self. However if you can put up a small tutorial on how to do it properly because I have emailed the support email and they haven't responded to me.


RE: Rope used for Crane - josemendez - 15-04-2019

(15-04-2019, 08:06 AM)flamingo Wrote: Hi There,
We Already have tried using your other asset Filo Simulator, however, because we cant add colliders to the rope, it goes through the crane itself and also the pulley it self. However if you can put up a small tutorial on how to do it properly because I have emailed the support email and they haven't responded to me.

Hi there,

Filo does not process collisions with anything that is not part of the cable path, also does not perform self-collisions.

However, by using only two particles in Obi you're also effectively preventing collision detection from happening, also preventing any actual rope simulation from taking place. You've reduced the rope to a single spring constraint, in fact.

Ropes are modeled in Obi as chains of particles, and collision detection is performed on a per-particle basis. So a very long cable with only two particles at its ends won't collide with anything.

Just use a rope with normal resolution (0.5 - 1) to get collision detection working.


RE: Rope used for Crane - flamingo - 15-04-2019

(15-04-2019, 01:20 PM)josemendez Wrote: Hi there,

Filo does not process collisions with anything that is not part of the cable path, also does not perform self-collisions.

However, by using only two particles in Obi you're also effectively preventing collision detection from happening, also preventing any actual rope simulation from taking place. You've reduced the rope to a single spring constraint, in fact.

Ropes are modeled in Obi as chains of particles, and collision detection is performed on a per-particle basis. So a very long cable with only two particles at its ends won't collide with anything.

Just use a rope with normal resolution (0.5 - 1) to get collision detection working.

So basically I wont be able to do exactly like what I have on this video(https://drive.google.com/file/d/1bl4HYzevBXlXDE3ptPml3a--7s2mxOOS/view?usp=sharing
I also have attached a pic of a crane that looks like the one im trying to build


RE: Rope used for Crane - josemendez - 15-04-2019

(15-04-2019, 01:41 PM)flamingo Wrote: So basically I wont be able to do exactly like what I have on this video(https://drive.google.com/file/d/1bl4HYzevBXlXDE3ptPml3a--7s2mxOOS/view?usp=sharing
I also have attached a pic of a crane that looks like the one im trying to build

Why not? It's a simple setup with 4 ropes, similar to the one included in the FreightLift sample scene.


RE: Rope used for Crane - flamingo - 16-04-2019

(15-04-2019, 07:16 PM)josemendez Wrote: Why not? It's a simple setup with 4 ropes, similar to the one included in the FreightLift sample scene.

When we do it with Filo, the pulleys goes out of the main hook, the highlighted part from the picture.


RE: Rope used for Crane - josemendez - 16-04-2019

Sorry but I don't understand the problem at hand.

(16-04-2019, 07:50 AM)flamingo Wrote: When we do it with Filo, the pulleys goes out of the main hook, the highlighted part from the picture.

Isn't this precisely what's supposed to happen?


RE: Rope used for Crane - flamingo - 23-04-2019

(16-04-2019, 07:28 PM)josemendez Wrote: Sorry but I don't understand the problem at hand.


Isn't this precisely what's supposed to happen?

The pulleys that are inside the highlighted gameobject comes out of there no matter what I do to make them stay inside.


RE: Rope used for Crane - josemendez - 23-04-2019

(23-04-2019, 10:38 AM)flamingo Wrote: The pulleys that are inside the highlighted gameobject comes out of there no matter what I do to make them stay inside.

How have you set up the pulley?