[javascript] Get the cellID having the pointID

Support
1

Hello

I know the existence of the function let cellIds = polydata.getPointCells(i, vtkTriangle);, where “i” is the pointId. I expect a list of cellIds as output (all cells than contain the point i), but this is not the case. Any hint on how to use this undocumented function?

Regards

2

Maybe I am asking the wrong question, Here there are other questions with the same goal:

  1. How can I get the ids of all the cells that contain a known point in a polydata?
  2. How can I get the neighbour points connected with a known point in a polydata?
3

Hello,

I believe that’s not the way getPointCells() is supposed to be called. Take a look at this: https://vtk.org/doc/nightly/html/classvtkPolyData.html#adf9caaa01f72972d9a986ba997af0ac7

take care,

PC

4

Thanks for your reply
However:

  1. I am on javascript
  2. I do call BuildLinks before.
  3. the function getPointCells does not accept vtlIdList as it doesn’t exists in vtk.js
  4. The returned object makes no sense to me and I can’t use it as even in the console only shows a common Dataset that I can’t get to work.

Regards

5

Hello,

You can make use of JS’ reflection/introspection and do some exploratory programming to discover the Dataset object’s methods and members. For example, to get all methods of the returned object:

(...)
let cellIds = polydata.getPointCells(i, vtkTriangle);

let methods = [];
for(var key in cellIds) {
    if(cellIds.hasOwnProperty(key) && typeof cellIds[key] == 'function') {
        methods.push(key);
    }
}

for (i = 0; i < methods.length; i++)
  document.writeln("method number " + (i+1) + ": " + methods[i]);

(...)

Side note: It is recommended to post under the “web” tag, where most vtk.js talk takes place. The “support” tag is mostly for non-web applications (mostly C++, Java and Python).

best,

PC

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