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Subject: Error in nurbs01 test


There is an error in the nurbs01 test in the test suite.  It appears that
the interpreter/viewer used to generate the reference PNG image ignored the
weights in the NURBS element.  To illustrate my point, I've generated an
equivalent file (without the boilerplate text labels) containing a NUBS
element which is unweighted by definition.  The knot vector is identical to
the nurbs01 test, and I've placed the control points at metrically
equivalent positions in VDC space.  This file views identically to the NURBS
element in the NURBS01.cgm file as depicted in the PNG image.  Applying
weights to the spline should significantly alter the shape of the curve.

You could do an equivalent test by using your convert program to remove the
weights in the NURBS element (i.e. set them all to 1.0) in the NURBS01.cgm
file.  You will see similar results.





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