Question

Extracting top and base lines from a vertical FME surface from a multipatch shapefile.

  • 8 March 2022
  • 1 reply
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Hi all,

 

I was wondering if anyone has any ideas to extract the top/base lines from vertical planes as a surface? It would be the lines in red/blue shown in the image below?

multipatch of vertical planes 

I've tried extracting the lines using a geometry part extractor but end up with triangular lines representing the surface.

I wondered about maybe converting to a pointcloud and then taking the max/min values for points with the same X/Y as the planes are all vertical.

 

Any ideas would be greatly appreciated.

 

Thanks!

 


1 reply

Userlevel 3
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For each face/vertical polygon you could do a CentrePointReplacer and CoordinateExtractor, this will tell you the Z level of the midpoint of each face. May have to GeometryCoerce to polygon to use a Chopper to turn each face into lines or points, merge the centrepoint Z onto them (by face ID, use a Counter earlier if they don't have an ID), and test whether the points are higher or lower than the midpoint. Hopefully that doesn't mess with the point order, so you can combine them back into lines to get the top and bottom lines for each face.

 

This relies on the top edge always being higher than the bottom edge of each face. And that the vertices are only on either the top or bottom edge.

 

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