Automated Centerline Extraction from Plan - Walls


So I’m faced again with the monotonous task of reconstructing a pre-exisiting building based on just plans/sections (This time for use in bim). In order to build the model correctly, I’ll need centerlines and center points of all elements. I’ve looked through the forum and found conversations about medial axes, and roof centerlines, but nothing really that directly addresses the problem at hand. The problem I have is that the wall polylines (taken from dwg) represent walls of different thicknesses and orientations, never perfectly perpendicular. Is there a method I’m missing? I realize I can just go through and draw centerlines manually, but with a multiple levels and multiple buildings, I’m hoping for a more automated solution.


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hi @hawke

Try this solution for the walls.

What I’m doing: Extracting all the edges from a wall, ordering by size (the longest edge representes the
the wall axis) and then theres two options. First one: Extract the smallest edges and then connect with a polyline by the curve middle vertices of each one. Or, extract the axis edges and then tween each other. They return the same results.

To be honest, I don’t know if this is exactly what you want due to the lack of images and examples of what you want or even if will work. BUT, this is the first step.

Take care!

Thank you for the reply! The walls I am hoping to address are a bit more complex, given that all of them are joined and keep varying in thickness. I have looked a bit further but it seems there is not a real viable solution. I think I am looking down the wrong route. Will rethink the entire process :smiley:

I just had a very quick look at this with a random form. Its not great, but maybe something like this could work; as long as the walls are rectilinear.

Next would be how to deal with the intersections. (16.5 KB)


Hi -
Have you seen this one?