[vtkusers] Opacity Problem (Please help me)

[Lisa Avila]

Hello Sandip,

I assume you are using a volume mapper to render the data? You'll need to 
either switch mappers (use the vtkVolumeTextureMapper2D instead of the 
vtkVolumeRayCastMapper - this is usually faster) or use some 
level-of-detail approach (using reduced resolution data sets, less rays 
cast, etc) to improve performance. You may want to download VolView from 
www.kitware.com to see how an LOD volume rendering strategy works in an 
application (load your data and see the speed / quality VolView is able to 
provide). You should be able to achieve something similar with VTK.

Lisa


At 12:38 AM 3/3/2004, sandip goyal wrote:
>Hi VtkUsers,
>                   I am working on the tomography data .My problem is to 
> make the objects transparent depending on the gray level selected by the 
> user from histogram .,i.e I want to make the data of particular gray 
> values to become transparent. For this I used
>
>  vtkTransferfunction SetPoint property and assigned the opacity to the 
> volume property . But this method causes my system to become too slow & I 
> am not able to do it iteractively with the mouse.
>
>Please suggest the method
>
>Thanking  You in advance
>Sandip Goyal
>
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