[vtk-developers] Class design for spline visualizations

[Lin M]

Hi Dr. Thompson,

I have a question about the knot vector and the knot insertion.
Currently the method for knot insertion is based on the algorithm from the
NURBS book where it always assumes that the first value and last value in
the knot vector repeat p+1 times. This makes the endpoints of the curve
always coincide with the first and last control points. As you mentioned
before, the knot vector may not always be like this and in such cases the
algorithm will fail. Is there any method to deal with this?

Best,
Lin

On Fri, Jun 26, 2015 at 1:06 AM, Lin M <majcjc at gmail.com> wrote:

> Hi Dr. Thompson,
>
> I have added a method in vtkPatchInterpolation to generate triangle
> strips for surfaces. I tested a cylindrical surface patch from the NURBS
> book and I think it's correct.
>
> Best,
> Lin
>
> On Thu, Jun 25, 2015 at 7:32 PM, David Thompson <
> david.thompson at kitware.com> wrote:
>
>> Hi Lin,
>>
>> > Your last message is quite informative. I think it is mainly to
>> implement a method in vtkPatchInterpolation which takes in a bezier patch,
>> number of samples and ...
>>
>>
>> That would be a great start. Eventually it would be nice to have
>> curvature-adapted surfaces, but just accepting a number of samples along
>> each axis will be something we need in any event.
>>
>> > ... return a vtkUnstructuredGrid?
>>
>> I would accept a vtkUnstructuredGrid pointer as input and insert into it
>> so that it is easy to create one grid with triangles from multiple patches.
>>
>>         David
>
>
>
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