Complex stair wall


Iam trying to offset edge curve of the curved stairs in order to create wall with 400mm. I didnt manage to create straight surface where iam able to extrude it in Z direction. Any smart tips?.

So i need endpoints of each subsurface to have the same Z coordinates but at the same time surface’s weight stays 400mm. As far as i know, is that corners needs sort of another solution approach.

Here is internalized GH file. (322.4 KB)


Because your polyline has angle variations in 2 directions, there is no mathematical solution to your problem that is :

  • 400 mm width offset
  • with constant Z
  • and an outer polyline that is continuous.

I added a C# component to your definition that offsets a polysurface to help visualize that.

You could remove those by creating an extrusion for each section of the stair, then cutting it by bisector planes of the walls. But the bottom and top surfaces do not join.

Or, you can cut by bisector planes built from the slope. But in this case, your outer surface doesn’t join.

If you want everything to join, then your wall has to have variable thickness, or the top and bottom surfaces can’t be planar. (331.6 KB)


Thanks a lot!