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Cut a hole in a Tin Surface


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Hello All

Im hoping someone can help me with a particular problem i am having trying to edit a Tin Suface.

I have created some FBX files of ground surfaces using point cloud data. Easy

However i now want to feed FME a DGN or DWG that contains outlines shapes, that i can use to cut holes in my FBX TinSurface.

I feel i have tried everything :(

I have tried also to remove the points from the point cloud and remake the mesh, with added holes, but the surface modeller joins the holes back up. eeerrrr!

Any help would be much appricated

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Best answer by owen 20 June 2018, 14:45

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6 replies

Userlevel 2
Badge +17

Hi @mortonprice,

It would be nice if FME could clip surfaces - this is something we are currently working on.

However, in the meantime, I do have a workaround for you, although it is a little complex:

- Use a SurfaceDraper to drape your cutting boundaries on the point cloud, setting Drape Method to MODEL

- Use a TINGenerator to create Triangles from the point cloud, with the draped boundaries used for Breaklines. This will ensure that the triangle boundaries follow the boundary lines

- Send the Triangles to a GeometryExtractor to store the geometry in an attribute

- Use a CenterPointReplacer to replace the triangles with points

- Clip the points by the boundary lines with a Clipper

- Restore the kept points triangle geometry with a GeometryReplacer

- Send the triangles to an Aggregator to build a multisurface

- Use a Triangulator to replace the multisurface with a more efficient mesh.

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Hi Dave thank you for you response, much appreciated. Being very new to FME i have created the work space to what i believe is as per your instruction. Does it look correct to you? i'm getting very unusual mesh creation in the inspector, and took almost 3 hours to create.

I have attached below a very basic image of what i am trying to achieve with FME.

Hopefully i'm very close

fme-clip-point-cloud.png

fme-expected-results.png

Badge +1

Hello. I have a similar approach you could try using the AreaOnAreaOverlayer with draped features and surface triangles which works quite nicely

Userlevel 2
Badge +17

Hi Dave thank you for you response, much appreciated. Being very new to FME i have created the work space to what i believe is as per your instruction. Does it look correct to you? i'm getting very unusual mesh creation in the inspector, and took almost 3 hours to create.

I have attached below a very basic image of what i am trying to achieve with FME.

Hopefully i'm very close

fme-clip-point-cloud.png

fme-expected-results.png

Hi @mortonprice,

 

Looks good, but you you need to use the Outside output of the Clipper instead of the Inside in order to remove the inside points.

 

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Hello. I have a similar approach you could try using the AreaOnAreaOverlayer with draped features and surface triangles which works quite nicely

Thank you Owen

 

 

Badge

Hi @mortonprice,

It would be nice if FME could clip surfaces - this is something we are currently working on.

However, in the meantime, I do have a workaround for you, although it is a little complex:

- Use a SurfaceDraper to drape your cutting boundaries on the point cloud, setting Drape Method to MODEL

- Use a TINGenerator to create Triangles from the point cloud, with the draped boundaries used for Breaklines. This will ensure that the triangle boundaries follow the boundary lines

- Send the Triangles to a GeometryExtractor to store the geometry in an attribute

- Use a CenterPointReplacer to replace the triangles with points

- Clip the points by the boundary lines with a Clipper

- Restore the kept points triangle geometry with a GeometryReplacer

- Send the triangles to an Aggregator to build a multisurface

- Use a Triangulator to replace the multisurface with a more efficient mesh.

Thank you Dave big help

 

 

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