# vtk Insertnextcell is too expensive
**URL:** https://discourse.vtk.org/t/vtk-insertnextcell-is-too-expensive/8866
**Category:** Dashboards
**Tags:** code, proposal
**Created:** [July 5, 2022, 9:48am UTC](https://discourse.vtk.org/t/vtk-insertnextcell-is-too-expensive/8866 "2022-07-05T09:48:40Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@zzusunquan](https://discourse.vtk.org/u/zzusunquan)
#### Post date: [July 5, 2022, 9:48am UTC](https://discourse.vtk.org/t/vtk-insertnextcell-is-too-expensive/8866/1 "2022-07-05T09:48:40Z")
```auto
// cell_x the triangle vertex index x
// cell_y the triangle vertex index y
// cell_z the triangle vertex index z
// _ptCellArray is a vtkCellArray object
// the code is c#
for(int i = 0; i < cellNum; i++)
{
var triangle = vtkTriangle.New();
triangle.GetPointIds().SetId(0, cell_x[i]);
triangle.GetPointIds().SetId(1, cell_y[i]);
triangle.GetPointIds().SetId(2, cell_z[i]);
_ptCellArray.InsertNextCell(triangle);
}
```
the above code is too expensive, every 100 points need 1ms. how can i accelerate it.
---
### Author:  [@Sebastien\_Jourdain](https://discourse.vtk.org/u/Sebastien_Jourdain)
#### Post date: [July 5, 2022, 10:32am UTC](https://discourse.vtk.org/t/vtk-insertnextcell-is-too-expensive/8866/2 "2022-07-05T10:32:23Z")
```auto
__ptCellArray.Allocate(cellNum * 3);
for(int i = 0; i < cellNum; i++)
{
__ptCellArray.InsertNextCell(3);
__ptCellArray.InsertCellPoint(cell_x[i]);
__ptCellArray.InsertCellPoint(cell_y[i]);
__ptCellArray.InsertCellPoint(cell_z[i]);
}
```
---
### Author:  [@zzusunquan](https://discourse.vtk.org/u/zzusunquan)
#### Post date: [July 6, 2022, 1:15am UTC](https://discourse.vtk.org/t/vtk-insertnextcell-is-too-expensive/8866/3 "2022-07-06T01:15:18Z")
thank you every much, your code worked！ It cost 3 percent of the previous time。
I have another question want to ask you, I use the following code
```auto
// _pd is a vtkPolyData object only with points
// the code is c#
var delaunay = vtkDelaunay2D.New();
delaunay.SetTolerance(0.001);
delaunay.SetInput(_pd);
delaunay.Update();
```
the above code cost 100 millisecond level while the \_pd have 10,000 points,.
So i use c++ CGAL build delaunay2D ， in c++ code, CGAL build delaunay2D cost 10 ms level with the same points. Then I Pass cell information to c#.
I think I’m using it wrong, can you tell me how to speed up the delaunay2D of vtk? I just need cell and point information。
---
### Author:  [@Sebastien\_Jourdain](https://discourse.vtk.org/u/Sebastien_Jourdain)
#### Post date: [July 6, 2022, 10:04am UTC](https://discourse.vtk.org/t/vtk-insertnextcell-is-too-expensive/8866/4 "2022-07-06T10:04:58Z")
You should post under another topic. For your second question, I have no idea.
---
### Author:  [@zzusunquan](https://discourse.vtk.org/u/zzusunquan)
#### Post date: [July 6, 2022, 10:21am UTC](https://discourse.vtk.org/t/vtk-insertnextcell-is-too-expensive/8866/5 "2022-07-06T10:21:39Z")
thank you very much， i will do it