# Proposal: adding a \`vtkPointCloud\` data structure

**URL:** https://discourse.vtk.org/t/proposal-adding-a-vtkpointcloud-data-structure/3872
**Category:** Development
**Tags:** proposal
**Created:** [July 29, 2020, 7:26pm UTC](https://discourse.vtk.org/t/proposal-adding-a-vtkpointcloud-data-structure/3872 "2020-07-29T19:26:44Z")
**Posts on this page:** 1
**Showing post:** 13

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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: [July 30, 2020, 4:13pm UTC](https://discourse.vtk.org/t/proposal-adding-a-vtkpointcloud-data-structure/3872/13 "2020-07-30T16:13:12Z")

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> [@Yohann\_Bearzi](#):
>
> If a poly data can be a point cloud as well as a triangular mesh, how do we grey out unapplicable algorithms?

It is an application implementation detail. There are certainly many options that are as good as checking the class of an object.

> [@Yohann\_Bearzi](#):
>
> Do we just allow them an do not produce anything when there is no `vtkVertex` cells?

The obvious choice would be to use all points of the vtkPolyData if there are no `vtkVertex` cells.

> [@Michael](#):
>
> To some extent, having a dedicated data structure for each simplex set is useful. Point cloud (0D) of course but lines-only (1D), triangles-only (2D) and tetrahedron-only (3D) data structures can be very useful as well.

Algorithm developers tend to prefer fine-grained class hierarchy (data structures and filters with narrow scope), while it makes applications simpler if there are less types (and they have broader scope). VTK so far hit a good balance and it would be nice to preserve this.

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