[vtkusers] render independent rgba components with vtkFixedPointVolumeRayCastMapper

[Adrian Albert]

Dear All


I am writing a program in VTK that takes some data, performs some
operations, and spits out a 4-component RGBA array. The RGBA has in fact
non-zero opacity values for the relevant regions, and for those regions also
the R value to a constant (255). I am rendering this array with
vtkFixedPointVolumeRayCastMapper, using independent input array components
(RGBA).

The probem is that I get a rather blocky appearence in my final image (I use
the heart.vtk and the ironprot.vtk datasets from the examples folder in
VTK).
I was wondering if this might be because the dataset resolution is low
(32x32x32), or because I do not set some parameters right in my input
dataset. Maybe VTK's volume rendering explicitly needs some gradient
computations, which is not done automatically when rendering, but rather
needs to be initialized when creating a new vtkImageData object and setting
the RGBA array as the object's scalars?


Any help will be greatly appreciated!
Best,
Adrian
-- 
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Adrian Albert
School of Engineering and Science
Jacobs University Bremen
Germany
Tel.: 00494212003258
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