title: Determine if point is inside triangle in 3D
body: <p>I am looking for acknowledgement on my perception of a method regarding determining whether a point is located inside a triangle or not in 3D.</p>
  
  <p>Given a ray in the form R(t) = e + td and a set of three points T = {V0, V1, V2} that forms a triangle in three dimensions, I know how to find the parametic equation for the plane that the three points form and how to determine if the ray intersects this plane or not. Lastly, if it intersects, I want to know if the intersection point actually is within the bounds of the triangles edges.</p>
  
  <p>Please see my picture below.</p>
  
  <p><a href="https://i.stack.imgur.com/ijwi8.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/ijwi8.jpg" alt="enter image description here"></a></p>
  
  <p>What I am thinking is that I can calculate the dot product between each edge vector and the vector that goes from the first edge in the edge vector towards the point and check if they are all positive. Like this:</p>
  
  <p><a href="https://i.stack.imgur.com/RlsDe.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/RlsDe.jpg" alt="enter image description here"></a></p>
  
  <p>If that is the case, the point should be inside the triangle. Right? Isn't this kind of the same method used for determining backfaces in computer graphics?</p>