Issues with Configurable Joint for a trailer and Truck Wheel clipping ground

Unity Engine
1

Hi, I have some issues I’ve managed to reach after battling with the Configurable Joint for ages to find a decent solution of Truck and Trailer.

The first is, I cannot seem to set it up so that the joint will not exceed an angle… this means that the truck will get past a certain angle with the trailer and then start clipping the ground + bouncing and then inevitably clipping the trailer with the cabin.
Below shows the angle at which it seems to start.

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These are my settings which I found on a video of someone else troubleshooting this… there seems to be very little in the way of a tutorial for people setting up trailers like this. Also note, at this angle everything is still comfortably stable. Apart from the 2nd back axle wheels, which make the truck bounce even more past about 70 degrees since they appear to be lower into clipping the ground for some reason once I launch the game, even though I set them at the same Y as the other axles. One last thing of note, once I start driving faster(10mph according to a test) with the truck, it will violently spin the truck through to one side(even worse if input is added at speed) and do a complete 180 into the trailer…

I tried the same setup with a Hinge-Joint and it would work to a degree, where I could limit the angle to -35 min and 35 max but this setup didn’t let the trailer straighten out after I stopped turning for some reason, and it would also automatically begin steering the truck left or right to the limit angle without any steering input for some reason… If I could fix those issues, the hinge joint would be far simpler to work with but I could not understand what the source of it happening was.

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If anyone could help me determine what I am doing wrong to cause these behaviours, I would greatly appreciate it, as I thought I reached a good solution that seems so close to correct, yet if I tried to make my game with this, it would be absolutely frustrating :confused: Note, if it’s something really obvious, this is my first time making a 3D game, and I haven’t fully made a 3D or a 2D game in Unity yet.

2

I have truck + trailer rigs working correctly. Some recommendations:

  • Set up a correct collider for the truck. You can use two convex colliders, one for the chassis and other for the cabin. These colliders may overlap.
  • Use free angular motion instead of limited, then enable collisions so there are no angle restrictions other than the own natural limits based on the collisions.

The collider setup may be tricky, as truck + trailer colliders must not be colliding in their natural positions.

3

I’m having the same trouble with the hinge joint: turn the truck left or right. Did you find a fix? When I try to check the use collider, it bounces everywhere.