ID 270341 - Hydra Viewer tab ignores a valid knots vector attribute when drawing B-Spline curves

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Problem summary
Changes made to the "knots" attribute are ignored and the HydraViewer defaults to "Open" and the LegacyViewer defaults to "Clamped".

Customer reported version
katana.n_a

Customer reported platform
n/a

Steps to reproduce
1) Import a B-Spline curve with a degree value greater than 1.

2) Create an OpScript and link the curve with CEL.

3) Add the following code. This will set the "geometry.knots" attribute value to a "Clamped" curve.


local controlPoints = Interface.GetAttr("geometry.numVertices"):getValue()local degree = Interface.GetAttr("geometry.degree"):getValue()local multiplicity = degree + 1local knotsLen = controlPoints + multiplicitylocal knots = {}for i=1, knotsLen do  if i <= multiplicity then    knots[i] = 0  elseif i > knotsLen - multiplicity then    knots[i] = knotsLen - (multiplicity*2-1)  else    knots[i] = i - multiplicity  endendInterface.SetAttr("geometry.knots", FloatAttribute(knots))

Results) In the HydraViewer, note that the curve does not reach the endpoints vertices.



For information regarding B-Spline curves, refer to the following links: 
https://pages.mtu.edu/~shene/COURSES/cs3621/NOTES/spline/B-spline/bspline-curve.html​​
https://pages.mtu.edu/~shene/COURSES/cs3621/NOTES/spline/B-spline/bspline-curve-open.html

Expected behaviour
The curve would be displayed as a "Clamped" curve in the HydraViewer

Actual behaviour
The HydraViewer ignores the "geometry.knots" attribute and draws the curve as an "Open" curve.
The LegacyViewer ignores the "geometry.knots" attribute and draws the curve as a "Clamped" curve.

Workaround
Unknown.

Reproduced by support
This bug has been reproduced in:
Katana 3.6v1 - Windows 10
Katana 3.5v3 - Windows 10
Katana 3.5v1 - Windows 10
Katana 3.2v6 - Windows 10
Katana 3.1v1 - Windows 10
Katana 3.0v1 - Windows 10
Katana 2.5v1 - Windows 10

Earliest version tested
Katana 2.5v1 - This issue appears to be in all versions of the product

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