Jump to content

  • Log In with Google      Sign In   
  • Create Account


Unit Vectors


Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.

  • You cannot reply to this topic
1 reply to this topic

#1 Anonymous Poster_Anonymous Poster_*   Guests   -  Reputation:

Likes

Posted 17 October 1999 - 11:06 AM

I've read a bunch of on-line 3D graphics tutorials and each keeps referring to the concept of unit vectors. Now I know what a unit vector is and how to make a vector into a unit vector. My questions is, for what purposes do you NEED to use unit vectors and when don't you need to use them (i.e. translations, rotations, plane-line intersection, etc)?

Thanks in advance for your help.


Sponsor:

#2 mhkrause   Members   -  Reputation: 122

Like
Likes
Like

Posted 17 October 1999 - 11:06 AM

You usually use a unit vector to avoid a division by the vector magnitude, since a unit vector has a magnitude of 1.

For example, if we were to define a directional light as a vector, v, and a vertex with normal, n, the light intensity at the vertex would be (v . n)/(|v|*|n|). If |v| and |n| are both equal to one (they are unit vectors), we could omit the costly divide, and just calculate light as v . n.





Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.



PARTNERS