Re: [Algorithms] Extracting scale from matrix

[Dave E. <eb...@ma...>]

From: "Pierre Terdiman" <p.t...@wa...>
> It would be interesting, yes...

Another source for SVD is my code MgcMatrix3.*
at the MgcCore.html page.  This implements the
algorithm from Golub's book (mentioned in this
thread).

For the original poster, if your matrix was computed
as a sequence of matrices, each having translation,
rotation, and a uniform scale, then the final product
must also have only uniform scale.  As someone else
pointed out in this thread, in this case you can just
look at the length of the first column of the 3x3 portion
of the homogeneous matrix to get the scale, then
normalize the three columns.  You should then have
a rotation matrix.

--
Dave Eberly
eb...@ma...
http://www.magic-software.com