Snip about feet IK for Unity

FeetIK.cs

  // somewhere in your charactercontroller
  
        public bool m_UseFeetIK = true;
        public float m_FeetIkOffset = 0.0f;

        void OnAnimatorIK()
        {
            if (m_Animator)
            {
                if (m_IsGrounded && m_UseFeetIK)
                {
                    var lf = m_Animator.GetBoneTransform(HumanBodyBones.LeftFoot);
                    var rf = m_Animator.GetBoneTransform(HumanBodyBones.RightFoot);
                    RaycastHit lhit;
                    RaycastHit rhit;
                    if (Physics.Raycast(lf.position + Vector3.up * 0.25f, Vector3.down, out lhit, 0.5f))
                    {
                        m_Animator.SetIKPositionWeight(AvatarIKGoal.LeftFoot, 1);
                        m_Animator.SetIKRotationWeight(AvatarIKGoal.LeftFoot, 1);
                        m_Animator.SetIKPosition(AvatarIKGoal.LeftFoot, lhit.point + Vector3.up * m_FeetIkOffset);
                        m_Animator.SetIKRotation(AvatarIKGoal.LeftFoot, Quaternion.FromToRotation(Vector3.up, lhit.normal) * transform.rotation);
                    }
                    if (Physics.Raycast(rf.position + Vector3.up * 0.25f, Vector3.down, out rhit, 1.0f))
                    {
                        m_Animator.SetIKRotationWeight(AvatarIKGoal.RightFoot, 1);
                        m_Animator.SetIKPositionWeight(AvatarIKGoal.RightFoot, 1);
                        m_Animator.SetIKPosition(AvatarIKGoal.RightFoot, rhit.point + Vector3.up * m_FeetIkOffset);
                        m_Animator.SetIKRotation(AvatarIKGoal.RightFoot, Quaternion.FromToRotation(Vector3.up, rhit.normal) * transform.rotation);
                    }

                }
                else
                {
                    m_Animator.SetIKPositionWeight(AvatarIKGoal.RightFoot, 0);
                    m_Animator.SetIKPositionWeight(AvatarIKGoal.LeftFoot, 0);
                    m_Animator.SetIKRotationWeight(AvatarIKGoal.RightFoot, 0);
                    m_Animator.SetIKRotationWeight(AvatarIKGoal.LeftFoot, 0);
                }
            }
        }