[Paraview] Cut plane surface rendering

[Philip A Cook]

Hi all,

I have volume brain data which I am slicing with cut planes. I set  
representation to "surface", Interpolation to "flat", and turn off  
"Interpolate Colors" under "Color". The surface polygons are colored  
in a strange manner, such that the pixels of my image appear to be  
sheared. I have placed an image showing the effect on the web:

http://www.seas.upenn.edu/~cookpa/paraview.png

The effect is the same for cut planes with a Y or Z normal. But if I  
make a plane with an X normal, the surface appears correct, ie the  
pixels are square.

I am running Paraview 3.0.0 on Mac OS X. The same effect is apparent  
on the Linux Paraview 3.0.0. The volume is a VTK scalar image  
containing RGB unsigned-char triplets for each voxel (in the image on  
the web I have mapped the scalars to a grayscale LUT). The header is:

# vtk DataFile Version 2.0
Camino RGB-scalar image
BINARY
DATASET STRUCTURED_POINTS
DIMENSIONS 112 112 60
SPACING 2.0 2.0 2.0
ORIGIN 0 0 0
POINT_DATA 752640
COLOR_SCALARS scalars 3

I can reproduce the same effect with MetaIO data, header

ObjectType = IMAGE
NDims = 3
BinaryData = True
BinaryDataByteOrderMSB = True
TransformMatrix = 1.0 0.0 0.0 0.0 1.0 0.0 0.0 0.0 1.0
Offset = 0.0 0.0 0.0
CenterOfRotation = 0.0 0.0 0.0
AnatomicalOrientation = LPI
ElementSpacing = 2.0 2.0 2.0
DimSize = 112 112 60
ElementNumberOfChannels = 3
ElementType = MET_UCHAR
ElementDataFile = LOCAL

I'm not sure if this is a bug or if I need to do something to the cut  
planes.

Thanks in advance,


Phil