[vtkusers] VTK-JS: How to get Position of actor

Katrin Hartwig katrin_hartwig at gmx.de
Mon Oct 23 06:50:44 EDT 2017

Hi Sebastien,

I stored the data as vtk data and used the vtkDataConverter which seemed 
to work fine. When I run the code, every actor appears exactly at the 
right place. So I guess the information in the vtk data must be correct 
(without ever using any function like "setPosition"). Though I do not 
understand why I cannot retrieve the information of their positions in 
the code.

Here is how I read my data files, it is a function I found in the 

function loadSegment(string, actor, renderer, i){
     const reader = vtkHttpDataSetReader.newInstance({ fetchGzip: true });
reader.setUrl(string).then(() => {
   reader.loadData().then(() => {
const mapper = vtkMapper.newInstance();

Any ideas what could be wrong?

Thank you for your help!

Am 20.10.2017 um 21:39 schrieb Sebastien Jourdain:
> Then I believe your dataset is not valid. How did you build it?
> On Fri, Oct 20, 2017 at 1:07 PM, Katrin Hartwig <katrin_hartwig at gmx.de 
> <mailto:katrin_hartwig at gmx.de>> wrote:
>     Hi Sebastian and Logan,
>     thank you a lot for your help and i apologize for my late answer!
>     Unfortunately I still could not solve the problem. I tried both
>     suggestions:
>     With *actor*.getCenter() I get the default-values (0,0,0) for each
>     actor. So I tried to get the information of the dataset as you
>     suggested:
>            dataset = mapper.getInputData();
>            bounds = dataset.getBounds();
>     By doing so I get the following error massage:
>     *       "getBounds called on an array with components of 1"*
>     The output of getBounds remains default because of the error.
>     As I could not find any solutions yet, I would be grateful for any
>     help!
>     Thank you
>     Katrin
>     *Gesendet:* Montag, 18. September 2017 um 16:38 Uhr
>     *Von:* "Sebastien Jourdain" <sebastien.jourdain at kitware.com
>     <mailto:sebastien.jourdain at kitware.com>>
>     *An:* "Katrin Hartwig" <katrin_hartwig at gmx.de
>     <mailto:katrin_hartwig at gmx.de>>
>     *Cc:* vtkusers <vtkusers at vtk.org <mailto:vtkusers at vtk.org>>
>     *Betreff:* Re: [vtkusers] VTK-JS: How to get Position of actor
>     Hi Katrin,
>     The actor position only describe the relative position to the
>     data, that's why by default they are always (0,0,0).
>     Which means its your source or dataset that has the information
>     about the position that you are looking for.
>     For example to find the bounds of a rendered dataset you can do as
>     follow.
>     dataset = mapper.getInputData();
>     bounds = dataset.getBounds();
>     // bounds is an array as follow:
>     // [ minX, maxX, minY, maxY, minZ, maxZ]
>     Hope that helps,
>     Otherwise you can learn more on the basic concepts behind VTK
>     here: https://www.vtk.org/vtk-users-guide/
>     <https://www.vtk.org/vtk-users-guide/>
>     Seb
>     On Mon, Sep 18, 2017 at 7:31 AM, Katrin Hartwig
>     <katrin_hartwig at gmx.de <mailto:katrin_hartwig at gmx.de>> wrote:
>         Dear all,
>         I am using a visualization of several actors with VTK-js.
>         Unfortunately, when using /actor.getPosition() /I always get
>         [0,0,0] as a result, no matter which actor I checked, although
>         they appear on different positions in my rendering window.
>         How can I get the real positions or centers of the different
>         actors?
>         As I am completely new to VTK-js and I could not find any
>         solutions to my problem, any help would be great!
>         Thank you
>         Katrin
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