Disconnected 3D isocontour in catalyst

Hi everyone,

In the CFD code I’m using, in which catalyst has been plugged, I’m trying to extract a 3D surface with the Contour filter and the following lines :

# create a new 'Resample To Image'
resampleToImage1 = ResampleToImage(Input=clip4)
resampleToImage1.UseInputBounds = 0
resampleToImage1.SamplingDimensions = [600, 80, 80]
resampleToImage1.SamplingBounds = [-0.05, 1.5, -0.02, 0.15, 0.0, 0.2]

# create a new 'Gradient Of Unstructured DataSet'
gradient1 = GradientOfUnstructuredDataSet(Input=resampleToImage1)
gradient1.ScalarArray = ['POINTS', 'Velocity']
gradient1.ComputeGradient = 0
gradient1.ComputeQCriterion = 1

# create a new 'Contour'
contour1 = Contour(Input=gradient1)
contour1.ContourBy = ['POINTS', 'Q-criterion']
contour1.Isosurfaces = [100000.0]
contour1.PointMergeMethod = 'Uniform Binning'

I run the code in parallel and everything works fine except that at the and I’m obtaining disconnected surface as result. Below is a comparison of a moving isosurface (5 successive snapshots) obtained directly from coprocessing (grey surface) and from post-processing of the full dataset gradient1 exported from coprocessing (see code above, black wireframe) :

As you can see, the wireframe surface is continuous whereas the grey one has a several separations (not all shown above). These separations are at fixed coordinates and therefore make me think to parallel computation issue.

Do you have any idea on the origin of the problem and if there is something to do to fix it ?

Thank you very much !