[Bug] Physical Constraints component missing joint preset

As the name implies, it seems like the joint preset is missing from the editor presets for the physical constraints component. Thus driving it into some bad behaviors that do not appear with the Physical Constraints actor.

You can read more about it in the second part


[old post showing the problem]

Hey guys.

I have been trying to make a tank with physically based suspension in UE4.
However, using the constraints (which would make sense as I basically want to make some mechanical links between parts… At least… That’s how I used to do mechanical engineering)… I cannot get it to be stiff. The locked axis acts as if they were some bones than can be bent.

Here is a screenshot of the way it acts while simulating:

http://puu.sh/h9fa0/db186743f7.jpg

Here is also the configuration used by the constraints between the suspension arms and the wheels:

http://puu.sh/h9fsi/d4d7025e39.jpg

http://puu.sh/h9fuH/4e4e11d4d1.jpg

I am really not getting it at the moment… If any of you could explain me how to make it work that way. I would be thankful forever. :slight_smile:

Here is a video showing the issue: Physical Constraint issue video
I removed the big wheels so it looks different a little bit. But the problem is the same. And you can see that somehow… It’s acting really weird.

Got the result to stabilize itself by making it symmetric. Having wheels on both sides helps.

But if the tank “jump” it still makes them all… Well… like a rubber joint (of it it takes any impact from any direction)

I will still welcome any help.

There’s another problem that showed up. It seems like when the pawn is dropped in the world and un-possessed. It works fine. But if I spawn in the world with it as default pawn, the physic does not “activate”. Making the tank sort of floating in the air and thus acting like “on ice”.

If anybody encounter the problem or have the slightest idea of how to fix it. I would be grateful.

Erio

Nobody has a solution/hint/any knowledge about it? :confused:

Bumping the question as this really seems to be a bug…

As far as I know even locked axes have some elasticity resulting from solver accuracy. You could try to increase position/velocity solver iterations for those meshes in their physics properties. Also, you could try setting projection to some very low value at risk of getting jitter. Also, adding another set of joints will also help stabilizing as that is an equivalent to more solver iteration for joint. Damping in joints or actors could also be very useful to avoid that constant vibration (maybe in the second set of joints where limits could be soft?). Have you found any solution?