How to prevent object from sliding when moving platform diagonally in Unity?-CodePudding

I am trying to implement a simple fork lift truck in Unity. Moving left, right, up and down is working fine: Box stays in place

Moving left/right and up/down at the same time (box moving diagonally) the box is sliding off the forks: Box is sliding off

Does anyone have an idea?

What i already tried to do:

When picking up the box, make it a child of the fork lift truck
Adding Physics Material 2D with high friction to forks and box
Set the x-velocity of the box to the x-velocity of the fork lift truck
Decreasing Movement- and Lifting speed of the fork lift truck
Decreasing fixed timestemp in Project Settings
Increasing Mass and Gravity Scale of the Box

Fork lift truck and the box both have a rigidbody2D attached with Body Type Dynamic and Collision Detection Continuous.

Currently iam moving the fork lift truck with the following code:

private void FixedUpdate()
    {
        //Moving Left/Right
        if (moveRight)
        {
            timeElapsedDeceleration = 0;
            rb.velocity = new Vector2(Mathf.Lerp(rb.velocity.x, drivingSpeed, timeElapsedAcceleration / 2), rb.velocity.y);
            timeElapsedAcceleration  = Time.fixedDeltaTime;
        }
        else if (moveLeft)
        {
            timeElapsedDeceleration = 0;
            rb.velocity = new Vector2(Mathf.Lerp(rb.velocity.x, -drivingSpeed, timeElapsedAcceleration / 2), rb.velocity.y);
            timeElapsedAcceleration  = Time.fixedDeltaTime;
        }
        else
        {
            timeElapsedAcceleration = 0;
            rb.velocity = new Vector2(Mathf.Lerp(rb.velocity.x, 0, timeElapsedDeceleration / 2), rb.velocity.y);
            timeElapsedDeceleration  = Time.fixedDeltaTime;
        }

        //Lifting
        if (moveForksUp && forks.transform.localPosition.y <= maxLiftHeight)
        {
            forks.transform.localPosition = new Vector2(forks.transform.localPosition.x, forks.transform.localPosition.y   liftingSpeed * Time.fixedDeltaTime);
            liftableMast.transform.localPosition = new Vector2(liftableMast.transform.localPosition.x, liftableMast.transform.localPosition.y   liftingSpeed / 1.5f * Time.fixedDeltaTime);
        }
        else if (moveForksDown && forks.transform.localPosition.y >= minLiftHeight)
        {
            forks.transform.localPosition = new Vector2(forks.transform.localPosition.x, forks.transform.localPosition.y - liftingSpeed * Time.fixedDeltaTime);
            liftableMast.transform.localPosition = new Vector2(liftableMast.transform.localPosition.x, liftableMast.transform.localPosition.y - liftingSpeed / 1.5f * Time.fixedDeltaTime);
        }
    }

The box should not slide off when moving e.g. left and up and the same time.

CodePudding user response：

when moving try to parent the box to the forklift's front thing and disable the rigidbody, something like this

if (isMoving)
      {
          box.trasform.parent = Lifter; 
          box.GetComponent<Rigidbody2D>().isKinematic = true;
      }
      else 
      {
          box.trasform.parent = null; 
          box.GetComponent<Rigidbody2D>().isKinematic = false;
      }

CodePudding user response：

Just add a fixed Joint 2D component to the box and connect it to the player whenever you want.

If it doesn't work, add two fixed joints