How to detect if player is on layer

Hey guys im trying to find a way to check if my player is on the ground by using a layermask
i thought i could just copy and paste my 2d code to my 3d project but that doesn't seem to work...
this is my 2d code:

Code (csharp):

1.  isGrounded = Physics2D.IsTouchingLayers(col, whatIsGround);

How could i convert this into something that would work for a 3d game?

 

It's similar, but you'd use Raycast/SphereCast/CapsuleCast instead. The basic idea is that you start from a point just about the character's feet, and spherecast downward, and see if you hit the ground. You can adjust the layermask used to decide what should be considered "ground". Here's the approach used by the StandardAssets rigidbody controller.

Code (CSharp):

1.  
2.         private void GroundCheck()
3.         {
4.             m_PreviouslyGrounded = m_IsGrounded;
5.             RaycastHit hitInfo;
6.             if (Physics.SphereCast(transform.position, m_Capsule.radius * (1.0f - advancedSettings.shellOffset), Vector3.down, out hitInfo,
7.                                    ((m_Capsule.height / 2f) - m_Capsule.radius) + advancedSettings.groundCheckDistance, Physics.AllLayers, QueryTriggerInteraction.Ignore))
8.             {
9.                 m_IsGrounded = true;
10.                 m_GroundContactNormal = hitInfo.normal;
11.             }
12.             else
13.             {
14.                 m_IsGrounded = false;
15.                 m_GroundContactNormal = Vector3.up;
16.             }
17.             if (!m_PreviouslyGrounded && m_IsGrounded && m_Jumping)
18.             {
19.                 m_Jumping = false;
20.             }
21.         }
22.  
23.  

 

An alternative method might be to have a trigger collider underneath the player. Then set

m_IsGrounded = true;

in OnTriggerEnter() and set to false in OnTriggerExit().