To do Rebar using Revit API

[Anonymous]

I am trying to provide rebar in beam in Revit. I want to draw the rebar in the beam using the diameter and spacing information saved in a external file (.csv in my case)

[Anonymous]

That should be fairly easily achievable. Take a look at these functions:
Rebar.CreateFromCurves Method
Rebar.CreateFromCurvesAndShape Method

Those two should help you achieve what you'd like.