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Matrix multiplication by vector and vice versa is a multiplication by at least one non-square matrix. But matrix addition, on the other hand, is something I hav
by pandaman 11y ago
Matrix multiplication by vector and vice versa is a multiplication by at least one non-square matrix. But matrix addition, on the other hand, is something I have never seen come up in graphics.
- deleted 11y ago[deleted]
- pandaman 11y agoI was never a fan of special cases in Math. Especially when it's not a special case. Saying that an element in the product matrix is a product of a row taken from one matrix and a column from another does not require matrices to be square and fits all possible applications of matrix multiplication already.
- codeofthedamned 11y agoTranslation itself is not a linear transformation. To simply translate a vertex is a matrix addition(subtraction) problem. The only reason that it is possible in the transformation matrix is because of the addition of the fourth parameter in a vertex [x y z 1] to create a homogenous linear system. This allows the translation to become a part of the transformation matrix.
- pandaman 11y agoI am not sure what you mean. If by "matrix addition" you meant adding vectors then it's obvious but adding actual matrices won't give you any translation operators because no matter how many matrices you have added together you still end up with a matrix, which, indeed, can only represent linear operators.
- codeofthedamned 11y agoI believe we are mincing words with the added confusion of two mathematical meanings for the word vertex in this discussion. The single row matrix, called a vertex, and a Euclidean vertex which we use to represent the points in the geometry, and happen to store in a vertex (matrix). I do agree with your statement.