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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hello,<o:p></o:p></p><p class=MsoNormal>I am looking for a widget like that found in VolView that allows the user to manually adjust points on an XY plot to adjust opacity settings. Basically it is an xy plot of histogram values with a line overlaid with three points on it. The two end points can be moved around on the graph(by the user with the mouse) in the x and y directions. The third point is in between these two end points and can be moved along the x direction. From these points, and corresponding line, a transfer function is derived for volume opacity. I’m wondering if this is written in vtk, itk, or some other toolkit, and if it is freely available. If not, could someone give me a good place to start for developing something like this? It should be a user control that could be placed on a form or window, rather than something displayed in a vtkRenderWindow. Can I use vtkMutableDirectedGraph?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks,<o:p></o:p></p><p class=MsoNormal>Sean <o:p></o:p></p></div></body></html>