SplineKnot Row (Geometry Section)
Contains x and ycoordinates for a spline's control point and a spline's knot.
A SplineKnot row contains the following cells.
Cell  Description 

The xcoordinate of a control point. 

The ycoordinate of a control point. 

One of the spline's knots (other than the last one or the first two). 
Remarks
Visio displays the definition of a spline in a Geometry section that contains a SplineStart row followed by one or more SplineKnot rows. The SplineStart row must be preceded by another kind of row, such as a MoveTo row, to indicate the first control point of the spline. The preceding row can be a LineTo, ArcTo, NURBSTo, PolylineTo, or EllipticalArcTo row if the spline follows a segment of that type.