how can i get the Slabedges (and start / endpoint of them).

What did you try?

I must admit that this isn't very straightforward and that there are two possible areas of confusion:

1. The property EdgeCount which gives the number of edges is on Face, not on SlabBase as one would usually expect.

2. The edges are retrievable as Curve2d (from SlabLoop) and as Curve3d (via GetEdgeCurveAt method).

Here's a fragment which determines Start- and EndParameter for each edge, calculates the average (let's call it "MiddleParameter") and transforms the resulting Point3d p from ECS to WCS.

~~Be warned that arcs are segmented into quarter circles.~~ for i in 0 .. slab.Face.EdgeCount - 1 do

let edge = slab.GetEdgeCurveAt(i, Autodesk.Aec.Arch.Geometry.FaceType.BaseFace)

let sp = edge.GetParameterOf edge.StartPoint

let ep = edge.GetParameterOf edge.EndPoint

let p = edge.EvaluatePoint (sp + (ep - sp) / 2.)

let p' = p.TransformBy slab.Ecs

ed.WriteMessage("\nId: {0}, Edge middle point: {1} ", i, p')

_{Edit: Circular slab was converted from MassElement. Need to look into arc segments.}