Debug Output

There are three good ways to debug values in unity depending on the situation.

1) Create a variable in the script and change it every frame to the value you want to debug. The inspector will then update every frame in playmode and show you the changed value.
Eg. Attach the script below to any object. debugValue will appear in the inspector. If you enter playmode, it will update every frame and be the time since you hit play.

Code (csharp):

1.  
2. var debugValue =5.0;
3. function Update () {
4.   debugValue = Time.time;
5. }
6.  

2) Debug.Log prints to the unity console. It also includes a stacktrace.

3) Debug.DrawLine is useful for visualizing 3D math. It draws a line in the scene view.