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WOW guys! thank you very much for all the suggestions about this topic.<br>You helped me a lot...and I hope this works soon.....<br>Many thanks!<br>Giancarlo<br><br>> From: david.gobbi@gmail.com<br>> Date: Tue, 16 Feb 2010 07:12:15 -0700<br>> To: daviddoria+vtk@gmail.com<br>> CC: vtkusers@vtk.org<br>> Subject: Re: [vtkusers] projections and transformations<br>> <br>> On Tue, Feb 16, 2010 at 6:56 AM, David Doria <daviddoria+vtk@gmail.com> wrote:<br>> >> It divides by the "w" coordinate, which is the 4th: (x, y, z, w).<br>> >> When you call TransformPoint(x,y,z) it creates a homogeneous<br>> >> coordinate (x,y,z,w) with w=1, and then multiplies it by the 4x4<br>> >> matrix. Then it returns (x/w, y/w, z/w).<br>> >><br>> >> David G<br>> >><br>> ><br>> > Ah right, again because it is a 4x4 projection matrix. What do you<br>> > think about adding vtkMatrix3x4 for typical "P = [KR | -KRC]" camera<br>> > projection matrices?<br>> <br>> The 4x4 matrix is the basis for the VTK transforms, so a vtkMatrix3x4<br>> would have to be converted to a vtkMatrix4x4 before it could be used.<br>> My opinion is that a 3x4 matrix would be kind of useless. A person<br>> can just construct a 4x4 matrix that does the same thing.<br>> <br>> David G<br>> _______________________________________________<br>> Powered by www.kitware.com<br>> <br>> Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html<br>> <br>> Please keep messages on-topic and check the VTK FAQ at: http://www.vtk.org/Wiki/VTK_FAQ<br>> <br>> Follow this link to subscribe/unsubscribe:<br>> http://www.vtk.org/mailman/listinfo/vtkusers<br> <br /><hr />Annoiato? <a href='http://www.messenger.it/raccoltaGiochi.aspx' target='_new'>Prova i giochi di Messenger!</a></body>
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