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Strength of Newton joints


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While building my rope bridge, I set a ball joint to every connecting cylinder of the ropes.

 

But now I've decided to be a little more realistic, and adjust the masses properly. The rope cylinders have a low mass (rope is not heavy), calculated by density and their volume. The planks have a mass of about 2 kilos, or about 5 pounds.

 

The problem is, the ropes do not seem to be able to handle that much tension. The bridge just falls into the abyss and the cylinders go crazy trying to hold it back.

 

In the real world, the masses are OK, so it's the joints that are having a problem.

 

The way I see it, a joint should be able to handle so much force, in that case the weight of the planks. And it shouldn't "expand", unless I want it to. It should stay solidly in place.

 

Now the joint stiffness has no effect on that. Lumooja told me the joint strength doesn't work, and to use forces to simulate it. So, what am I doing wrong here? There seems to be a physics parameter I don't have control on, that is, the strength of the joints.

 

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Cool.

 

I spent an evening trying to keep wheels on a helicopter. It was impossible, they kept falling off when you put any sizeable mass on them. I thought it was just me (being a bit tubby these days through sitting all day and eating comfort food).

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  • 2 weeks later...

I also think you will have problems if one body has a large mass, and a connected body has a small mass. If you need greater joint power, the problem is it will lead to more vibration and instability, because it will add a lot more energy into the system.

My job is to make tools you love, with the features you want, and performance you can't live without.

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In a real-life scenario, you can attach an elephant to a rope with a strong metal joint. it won't "vibrate" and go "unstable" if the joint is strong enough.

A computer simulation is not real life. If you were using PhysX, there would be even more arbitrary problems like this that don't match reality.

My job is to make tools you love, with the features you want, and performance you can't live without.

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