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Wheel Collider: Understanding scale

Discussion in 'Physics' started by RogerGu, Dec 13, 2015.

  1. RogerGu

    RogerGu

    Joined:
    Dec 23, 2014
    Posts:
    5
    I am trying to make super simple vehicles with two wheels each like a steam roller or flintstones style car. The Wheel colliders seem to be flat circles rather than cylinders. What properties do I update to adjust this? If it is the transform scale, should the green outline of the collider show the width of the cylinder?
     
  2. bluescrn

    bluescrn

    Joined:
    Feb 25, 2013
    Posts:
    642
    From my experiments with them, I'm guessing that the implementation of wheel colliders is based on downwards raycasts - there's not a physical disc/cylinder collider there. (To simulate a wider wheel with larger contact area, you'd mess with the sliding/friction value)

    So they won't work for open-wheel vehicles - If the exposed wheel hits something that isn't fairly flat, bad things happen - only the cube 'body' in this test is actually behaving like a solid object:



    (It's probably possible to combine a wheel collider with real colliders on/around the wheels to avoid this case. But if you want something like a monster truck that can climb over very rough terrain+obstacles, the standard wheel collider probably isn't an option)
     
    Last edited: Dec 13, 2015
    RogerGu likes this.
  3. pauloaguiar

    pauloaguiar

    Joined:
    May 13, 2009
    Posts:
    700
    Try add Mesh collider + convex to the wheels and add physics meterial "Ice" and test again.
     
  4. RogerGu

    RogerGu

    Joined:
    Dec 23, 2014
    Posts:
    5
    Thank you!