Example for extracting a single cell from a polydata into a new dataset

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1

Hi,

could anyone provide me with an example for doing the following operation:
Let’s say I have a polydata.
I want to extract one cell (knowing its ID) into a new dataset (which I will then display as a wireframe to highlight that cell).
@Sebastien_Jourdain suggested doing shallow copy of my polydata but I’m not sure how to do that and then only having a single cell in that copy ?
Is it because the copy only deals with points and I then have to manually build my single cell ?
Thanks for your help

2 
const selection = vtkPolyData.newInstance();
const selection.shallowCopy(originalDS);
// selection.getCellData().clear();
const cell = [];
const targetCellId = 234;
let cellOffset = 0;
let currentCellId = 0;
const originalCells = originalDS.getPolys().getData(); // assuming only polys

// find cell
while (currentCellId < targetCellId) {
  cellOffset += originalCells[cellOffset] + 1;
  currentCellId++;
}

// extract a copy of the found one
for (let i = 0; i <= originalCells[cellOffset]; i++) {
  cell.push(originalCells[cellOffset+i]
}

// override the original cells with the one we created
selection.getPolys().setData(Uint16Array.from(cell))
1 Like
3

Great thanks a lot !