In this [question][1] I asked how to deform an object with an spline using animation nodes. The technique explained there the deformation considers all 3 dimensions tilting the output object, but what if I want to deform this object locking the tilt as if it was done with a 2D spline but still deform in a 3d space?, exactly as it is done [here][2].   


EDIT

Using @Omar Ahmad answer I managed to get the results I needed. but I'm still a little bit confused. The following image shows the resulting graph:

 [![enter image description here][3]][3]

I'm not quite sure if the new computed normal is correctly linked as in order to get the desired results I was forced to increment its Z value up to 1000.


  [1]: https://blender.stackexchange.com/questions/139150/deform-geometry-along-spline-in-animation-nodes/139167?noredirect=1#comment239278_139167
  [2]: https://blender.stackexchange.com/questions/114469/curve-modifier-deformation-only-on-z-axis#114481
  [3]: https://i.sstatic.net/RC74u.jpg