[vtk-developers] Class design for spline visualizations

[David Thompson]

Hi Lin,

> I get it now. Previously I was thinking of bezier patches so we need explicit definition about the degree to each dimension given a control point array. We are now considering NURBS whose degree of interpolant has been implicit defined together by the knot vectors and control points (degree + number of control points = number of knot vector entries) but if we assume all the control points for all patches are stored in one vtkStructureGrid instance (the points are ultimately stored in the vtkDataArray* vtkStructureGrid->GetPoints()->GetData()), we still need to know where the i-th patch begins in the vtkDataArray. 

Right, but this can be inferred from the knot vector and the regular arrangement of the points in a spline's control polygon.

> 
> What we want to implement now is to use vtkMappedDataArray to retrieve a "fake" vtkDataArray for one patch from the original vtkDataArray.

Exactly!

	David