[vtkusers] Piecewise Function for Volume Rendering

[Yuan Jin]

Hi John,

Actually, I have developed such a vtkTransferFunctionWidget in TkInter, but 
I still need to know the optimal piecewise function like the one in 
volcutknee.py to speed up the setup of the function, therefore, I guess 
there are some ways to do it.

Thanks for your help

Yuan


>From: anast.jm at pg.com
>To: vtkusers at public.kitware.com
>Subject: Re: [vtkusers] Piecewise Function for Volume Rendering
>Date: Thu, 22 Aug 2002 10:18:21 -0400
>
>
>Yuan,
>
>This is always a tough one. Every volume is different it seems so defining 
>the
>values can take some work. Most programs use interactive adjustment of the 
>point
>position and value to get it right, however there is not a standard 
>"interactor"
>implemented in vtk. I've always wished for a vtkTransferFunctionWidget! In 
>tcl
>you can hook up some simple sliders to change the values but its a bit of a 
>pain
>and not as flexible as sliding points and values around on a graph. I've 
>had in
>the back of my mind to build an interface in tcl by picking/moving points 
>in a
>2D render window but haven't got to it yet. To see a nice implementation of
>interactivity in the setup of the opacity, color and gradient transfer 
>functions
>download the trial version of VolView from the Kitware web site.
>
>Certainly examining the histogram range and shape could lead to to some 
>good
>estimates of the transfer functions but its typically non-linear and would 
>take
>some extra work to get it just right. (I think transfer functions are like 
>art,
>a matter of taste to some)...certainly possible though. It all really 
>depends on
>what you want to emphasize, which is why this is often done
>interactively......john
>
>
>
>
>
>  Internet Mail Message
>  Received from host:      public.kitware.com
>  [24.97.130.19]
>
>
>
>From: "Yuan Jin" <yjin76 at hotmail.com>@public.kitware.com on 08/22/2002 
>01:47 AM
>GMT
>
>          "Yuan Jin" <yjin76 at hotmail.com>           To:   
>vtkusers at public.kitware.com
>                      @public.kitware.com           Cc:    (bcc: John 
>Anast-JM/PGI)
>                                            Subject:      [vtkusers] 
>Piecewise Function for
>                                                 Volume Rendering
>                                 Sent by:
>        vtkusers-admin at public.kitware.com
>                      08/21/2002 09:47 PM
>
>
>
>
>
>
>Hi all,
>
>Does anyone have experience in setting up the piecewise function for the
>volume rendering? ie. which points should be added to the piecewise
>function? Is the histogram for the 3D image helpful?
>
>For instance, in the example: VolCutKnee.py
>
>white_tfun = vtkPiecewiseFunction()
>white_tfun.AddPoint(0,1.0)
>white_tfun.AddPoint(255,1.0)
>tfun = vtkPiecewiseFunction()
>tfun.AddPoint(70,0.0)
>tfun.AddPoint(80,1.0)
>vol_prop = vtkVolumeProperty()
>vol_prop.SetColor(white_tfun)
>vol_prop.SetScalarOpacity(tfun)
>
>How to find out tfun.AddPoint(70,0.0) and tfun.AddPoint(80,1.0) ?
>
>Thanks a lot,
>
>Yuan
>
>
>
>_________________________________________________________________
>MSN Photos is the easiest way to share and print your photos:
>http://photos.msn.com/support/worldwide.aspx
>
>_______________________________________________
>This is the private VTK discussion list.
>Please keep messages on-topic. Check the FAQ at: <
>http://public.kitware.com/cgi-bin/vtkfaq>
>Follow this link to subscribe/unsubscribe:
>http://public.kitware.com/mailman/listinfo/vtkusers
>
>
>
>_______________________________________________
>This is the private VTK discussion list.
>Please keep messages on-topic. Check the FAQ at: 
><http://public.kitware.com/cgi-bin/vtkfaq>
>Follow this link to subscribe/unsubscribe:
>http://public.kitware.com/mailman/listinfo/vtkusers




_________________________________________________________________
Join the world’s largest e-mail service with MSN Hotmail. 
http://www.hotmail.com