Hinge Constraints causing Wheelchair to bounce

Hey there!
I have been making a wheelchair using hinge constraints so it can have functioning wheels.

However, it seems the hinge constraints are behaving oddly, as it causes the chair to bounce up and down when it remains stationary.

Note that the hinge constraints actuator type is set to none and that there is no force being applied to the chair:

I want it so that the wheelchair can function without experiencing this issue.

If needed, here is the wheelchair model itself:

Any help is appreciated! Thanks!

I would guess that possibly the wheel’s hitbox is intersecting with the rest of the wheel chair.

Often with cars and stuff people make the wheels and the chassis have separate collision groups, where the wheels can’t collide with the chassis but everything else collides with them normally.

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Thanks for the response! I gave the wheelchair a different collision group than the hitbox like you suggested, but the issue persists. However, removing the hitbox fixes the problem entirely, but I would prefer it to stay. The hitbox was also can collide off from the start, so it shouldn’t be interfering with the wheels. Could it still be an issue with the hinge constraints or am I doing something wrong?

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Screenshot 2024-03-05 at 10.51.25 PM

Ah, this is a pretty tricky one. The part named Handle is really massive (and invisible!) and is forcing the chair into the ground with its mass. Setting the handle to massless fixes it.


Something weird is going on here.
I set the VehicleSeat to Active so I could sit on it.
I test it and it bounces around. One or both front wheels start spinning really fast.
I anchored the seat, nothing moves, the wheels don’t spin strangely.
I unanchored the seat and tested again, but with the Main, both W parts in the steering wheels, and both Wheel parts with CustomProperties turned on and Density set to 5. The seat still bounces and then freezes. I sit in it and it moves again, but freezes again.

Edit: just read @BendsSpace’s post. They are correct.
I also usually set my vehicles Mass prettly light and set the wheels Density to around 2. It seems to keep vehicles pretty stable.
Smaller vehicles like this are generally tougher to tweak since the player’s mass can exceed the mass of the vehicle and cause issues.
Good luck!


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