Configurable Joint for Wheel Suspension

Unity Engine
1

First of all there’s a similar topic here however my issue seems to be different because the topic didn’t help me. I’m working on a trial - style 2D vehicle system (one body, two wheels):

However I’m not using wheel colliders but actual rigidbodies with rotation and position constraints which are parented to the body. What I want is to use the configurable joint to simulate the suspension of the vehicle. The problem is that the configurable joint doesn’t seem to react to my settings. Now, here’s what I have:

  • Chassis: Rigidbody with mass 200. Z movement restricted and X and Y rotation restricted.
  • Wheels: Rigidbodies with mas each 75 with same restrictions as the chassis.
  • Wheels are parented to the chassis
  • Each wheel has a configurable joint connected to the chassis with the following settings:

X and Z Motion - Locked , YMotion limited
Angular motion - all free
Linear limit:
Limit 0.5
Bounciness 0.1
Spring 10
Damper 1

The above doesn’t do anything - there’s no suspension effect. However if I set the Anchor from 0, 0, 0 to 0, 1, 0 for example, the suspension starts to work but no matter how I set the Linear Limit the suspension stays the same. For example I want a bigger suspension effect but I also want it to be fast so the vehicle doesn’t look awfully heavy but I can’t set it up.

Can somebody guess what seems to be the problem ?

Also if there’s is a better way to achieve the suspension feel free to offer it. I tried it with a spring joint first but because of the lack of constraints I moved to configurable joints.

2

The spring force is calculated by measuring how far the spring has been stretched and then multiplying that distance by the spring value that you set in the inspector. You are using rather large masses for the rigidbodies and if the models are also quite small then the spring force times distance calculation will still only yield a small force, possibly less than the weight of the chassis. Generally, the physics engine works better with small masses rather than “realistic” values, so you could try setting the wheel rigidbodies’ masses to, say, 1 and the chassis’s mass to 4. However, you may need to experiment a bit before getting satisfactory results from the physics here.

3

Hey man i’m doing the same thing but I can’t figure out how to make the wheel spin, lots of confusing options with little explanation that I can find …