[vtkusers] How to make vtkImageViewer2 to show an actor only in a certain depth

[David Gobbi]

I'd like to second this: a cutter is the right way to go.  Clipping planes are
the wrong way to go.  When you use clipping planes, the result depends on
the angle of your sphere polygons with respect to the camera, so the resulting
"circle" will have some line segments that look too thick, and some other line
segments that are so thin that they become invisible.

I've used vtkCutter for this and it is plenty fast enough.  In fact I've even
run the cutter's output through vtkTubeFilter to make the cut outlines look
thicker, and it was still fast enough even with that extra step.

  David


On Mon, Jun 16, 2014 at 12:27 PM, Miro Drahos <mdrahos at robodoc.com> wrote:
> Hi Sam,
> if your surface is not too large, it shouldn't hinder the performance much.
> I cut a polydata with ~20k vertices interactively, by sliding the cut plane
> and there are no issues (on a lower-end NVIDIA GPU).
>
> To answer your question: there is another way -- you could use clipping
> range of the camera and let the camera frustum cut your surface, but I would
> advise against this hack. Just stick with the vtkCutter. It uses a point
> locator (sort of a hash-table) to speed up the lookup and really shouldn't
> give you much of performance penalty.
>
>
>
>
>
> On 06/16/2014 10:43 AM, Sam Raby wrote:
>
> Thanks for the feedback.
> Consider a scenario that you have a slider-bar which scroll through DICOM
> files and then this "clipping" has to happen for each slice repeatedly. I am
> afraid that this would not allow the slider-bar to smoothly move, but maybe
> there no faster way presently.
>
> Is there a way to hide only a part of an actor, and not the entire actor
> (instead of cutting it)?
>
> -Sam
>
>
> On Mon, Jun 16, 2014 at 12:21 PM, Miro Drahos <mdrahos at robodoc.com> wrote:
>>
>> If what you want is to cut your sphere and visualize the intersection of
>> the sphere (a circle) with the viewer plane, use vtkCutter.
>> The sphere polydata is the input, the reslice plane is the cutFunction.
>> HTH,
>> Miro
>>
>>
>>
>> On 06/13/2014 02:34 PM, Sam Raby wrote:
>>>
>>> Hello,
>>>
>>> I have a simple actor as simple as sphere and would like to show it in a
>>> certain depth in vtkImageViewer2.
>>>
>>> vtkImageViewer2 displays all the actors which are above the image, but is
>>> there a way to force vtkImageViewer2 to show only that part of sphere actor
>>> that is in the same depth as the image?
>>>
>>> I saw a post [1] stating that the following may do the job, but I could
>>> not make it work:
>>>
>>> interactorStyle->AutoAdjustCameraClippingRangeOff().
>>>
>>> thanks,
>>> -sam
>>>
>>> [1] http://www.vtk.org/pipermail/vtkusers/2008-August/047565.html