# vtkAppendPolyData - performance increase?

**URL:** https://discourse.vtk.org/t/vtkappendpolydata-performance-increase/1590
**Category:** Support
**Created:** [August 16, 2019, 6:20am UTC](https://discourse.vtk.org/t/vtkappendpolydata-performance-increase/1590 "2019-08-16T06:20:37Z")
**Posts on this page:** 1
**Showing post:** 8

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### Author: ![lassoan](https://discourse.vtk.org/user_avatar/discourse.vtk.org/lassoan/32/50_2.png) [@lassoan](https://discourse.vtk.org/u/lassoan)
#### Post date: [August 19, 2019, 7:02pm UTC](https://discourse.vtk.org/t/vtkappendpolydata-performance-increase/1590/8 "2019-08-19T19:02:30Z")

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> [@Mskovmand](#):
>
> In addition to this mesh, I’m trying to show some specific points. In the aforementioned example, we are talking roughly 60,000 points.
> 
> These points are interacted with, individually, as they carry information (a caption box is displayed when the actor is picked). This leads me to think that they should be displayed as individual actors, like spheres.

Showing 60k points is easy, it should be work without any extra effort at screen refresh rate.

Interacting with 60k points is a completely different story. You can certainly not use a separate actor for each point as it would be extremely slow. You need to use a glyph filter or mapper and take care of point interactions yourself, since existing interactive VTK widgets use a few actors for _each_ interactive handle. There is an implementation of point and curve widgets in 3D Slicer that allow interaction with thousands of points (interaction starts to become less fluid when you reach about 10k, because we stopped optimizing performance when everything was fluid at 1k). See some more details in this post: [picking glyphs vtkGlyph3DMapper - #2 by lassoan](https://discourse.vtk.org/t/picking-glyphs-vtkglyph3dmapper/1618/2).

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