## RE: [Algorithms] Quaternions or Matrices

 RE: [Algorithms] Quaternions or Matrices From: Stefan Maton - 2003-02-28 09:48:41 ```> which gives a pointer to > http://www.gamedev.net/reference/articles/article1199.asp that has an > interesting debate about this. Well, I don't think that helps me to understand why quaternions aren't used more often. IMO the article doesn't take into account the effective number of operations used to do a transformation. Using a 4x4 matrix (containing rotation, scaling and translation) it takes 64 multiplications and 64 add operations to combine two matrices (matrix multiplication). The same can be done with 51 multiplications and 39 add operations using a quaternion and 2 vectors. Yes, there's a overhead because you have to convert the quaternion into a matrix when passing it to OpenGL/DirectX but this takes 17 mult and 15 add operations making it 68 mult and 54 add operations to create a transformation matrix. Now, this doesn't make much benefit, if you only have the world and one object to combine. But it makes a big difference when you do it on a large number of objects. Kind regards, Stefan ```