Construct center line element between two curves/lines


 Product:MicroStation
 Version:V8i (SELECTseries)
 Environment:N\A
 Area:Base Geometry
 Subarea:N\A

How can a center line be drawn between two non parallel curves or straight lines?

Background

For example, take a river, or a road/highway where the width of the median may vary. I want to be able to pick the river or road edges and automatically get the center line (or as close as possible).

Steps to Accomplish

One method to try and achieve this could be as follows: -

1. In a 3d file, draw a construction line ( Yellow lines ) that connects at the ends of the curb lines

2. Use the 'Sweep Surface Along Curves' tool to generate surface (  tool settings : ' Sweep One along 2 or 3 ' / ' Arc Length' / ' Keep Path ' )

3. Use the ' Extract Iso-Curves ' tool to obtain the center line by clicking on the surface and snapping to the mid point (setting the 'Iso Value' to 0.5 may also work) of the yellow construction line.

4. Delete the surface (unless required)

Note: The center line in the above example may not be based on the point of perpendicular / tangency to the outside lines required.

See also

Unable to create correct surface with 'Swept Surface along Curves'

Other language sources

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Nederlands

 Original Author:

Conor King (With thanks to Carl Myhill)