[vtkusers] [VTK] Building a custom oriented arrow

[Jon Haitz Legarreta]

Bill,
thanks for the suggestion. I'll try to follow the advice and create it that
way.

On the other hand, D.Doria also pointed some geometry issue; the "middle"
sphere was to be located at 1/3 from the startPoint, and the right location
for that is:

  midPoint[i] = startPoint[i] + (endPoint[i] - startPoint[i]) /3;

instead of what I was using.

So thanks both of you for having taken some time to help.

Kind regards,
JON HAITZ


On 2 May 2014 15:02, Bill Lorensen <bill.lorensen at gmail.com> wrote:

> This seems a bit too complicated. Think of the "custom" arrow as a single
> model. Create the model in the original normalized space of the arrow
> source. "Build" your model components, place them in the space and compose
> them into a single polydata using the append polydata filter. Then apply
> the the transforms of the example to the single polydata. Colors can be
> assigned to the individual components of the custom arrow by setting the
> cell data of each component.
>
> It will take a bit of fiddling to get the initial model correct. But then
> it should be easily transformable.
>
>
>
> On Fri, May 2, 2014 at 2:46 AM, Jon Haitz Legarreta <
> jhlegarreta at vicomtech.org> wrote:
>
>> Hi there,
>> I'm trying to build a custom oriented arrow based upon the OrientedArrow
>> example [1]. However, I seem not to be doing it right.
>>
>> I'm trying to set a sphere in the middle of the arrow, as well as two
>> orthogonal lines centered at that point.
>>
>> The sphere is not located in the middle of the arrow, and the lines, even
>> if orthogonal do not cross in the center of the sphere.
>>
>> I guess it has to do with the transformations (scale and rotation), but
>> cannot make head or tails of it.
>>
>> On the other hand, I cannot guess how to center the point where the lines
>> cross at the center of the sphere.
>>
>> When the arrow's head and base are not random, but defined with some
>> known values, it seems to work well.
>>
>> Attached, the screenshots of the attempt, the version with some known
>> points (which seems to be OK), and the corresponding .cxx and
>> CMakeLists.txt.
>>
>> Thanks,
>> JON HAITZ
>>
>> [1]
>> http://www.vtk.org/Wiki/VTK/Examples/Cxx/GeometricObjects/OrientedArrow
>>
>>
>>
>>
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>
>
> --
> Unpaid intern in BillsBasement at noware dot com
>
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