display freezes


I'm currently working on a 3D dataset and using the
isoContour to generate a surface plot. I only get an
image at a certain isoSurface value (1.085). At a
surface value of zero which is the correct value for
my data, I get no image and the display freezes when I
try to rotate it.

I am reading in a netCDF file, the mathType is
(x,y,z)-> data.
mappings are:
x->X Axis 
y->Y Axis
z->Z Axis

Thanks in advance,


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