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count number of points in a solid

  • 29 November 2018
  • 4 replies
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Hi FME community

 

 

I try to count the number of points (from *.las point cloud) in a solid. The solid comes from an extruded polygon.

 

 

The goal of it is to figure out if the point cloud matches an existing 2D CAD Plan. To do this I take the polyline of the walls and extrude them. Afterwards I would like to count the number of point inside the extruded solid (wall). If this results in many points I can assume that the wall is correct - if not the wall must be incorrect.

 

 

It would be great if someone has any idea and can help me. I only struggle with the count of the points in the solid.

 

 

Thanks in advance and kind regards form Switzerland

 

Dominik
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Best answer by dominik 29 November 2018, 16:07

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4 replies

Userlevel 2
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Hi, if the solid is a simple one which is created by extruding a flat polygon towards z-axis direction, a possible way is:

  1. BoundsExtractor: Extarct zmin and zmax of the extrusion solid.
  2. SurfaceFootprintReplacer: Replace the solid with a 2D polygon.
  3. Clipper (Check the Merge Attributes option): Clip the point cloud by the polygon.
  4. PointCloudFilter: Create a point cloud consisting of points whose z-coordinate are within the zmin and zmax.
  5. PointCloudPropertyExtractor: Count the number of the resulting point cloud.
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@dominik

You can use a clipper for that

Use your solid as clipper.

 

Badge +1

Hi takashi

 

 

Thanks for your effort and answer. In the meantime I figure out a similar way:

 

1. I use the 2DForcer for the point cloud (so every point is on z=0)

 

2. I use an PointOnAreaOverlayer to count the number of points inside the wall

 

 

This works perfect for me!

 

 

Thanks anyway!

 

Dominik
Userlevel 2
Badge +17

@dominik

You can use a clipper for that

Use your solid as clipper.

 

I didn't know the Clipper supports 3D clipping on point cloud. Good to hear :-) Thanks.

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