title: How to get create a vector from a curve?
body: <p>Maybe I'm misunderstanding the concept of 'curve' in Revit API, but I'm basically trying to create a vector from a curve. What I was guessing was creating a vector from both end points of the curve(using GetEndPoint class), but it seems like it's not a thing in Revit API.</p>
  
  <p>I need you guys' help! Thanks!</p>