Geometry_Engine: Add controls to external edges for mesh

Geometry_Engine/Query/ExternalEdges.cs

@@ -26,6 +26,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.ComponentModel;
 
 namespace BH.Engine.Geometry
 {
@@ -35,6 +36,7 @@ public static partial class Query
         /**** Public Methods - Surfaces                 ****/
         /***************************************************/
 
+        [Description("Gets the external edge curves of the Extrusion.")]
         public static List<ICurve> ExternalEdges(this Extrusion surface)
         {
             ICurve curve = surface.Curve;
@@ -61,13 +63,15 @@ public static List<ICurve> ExternalEdges(this Extrusion surface)
 
         /***************************************************/
 
+        [Description("Gets the external edge curves of the Loft as the curves of the Loft.")]
         public static List<ICurve> ExternalEdges(this Loft surface)
         {
             return surface.Curves; //TODO: Is that always correct?
         }
 
         /***************************************************/
 
+        [Description("Gets the external edge curves of the Pipe. If the Pipe is capped, this returns a circle at each end of the centre curve. If the pipe is uncapped, this method returns an empty list.")]
         public static List<ICurve> ExternalEdges(this Pipe surface)
         {
             if (!surface.Capped)
@@ -85,13 +89,15 @@ public static List<ICurve> ExternalEdges(this Pipe surface)
 
         /***************************************************/
 
+        [Description("Gets the external edge curves of the PlanarSurface as its ExternalBoundary.")]
         public static List<ICurve> ExternalEdges(this PlanarSurface surface)
         {
             return new List<ICurve> { surface.ExternalBoundary };
         }
 
         /***************************************************/
 
+        [Description("Gets the external edge curves of the PolySurface the external edge curves of all of its parts.")]
         public static List<ICurve> ExternalEdges(this PolySurface surface)
         {
             return surface.Surfaces.SelectMany(x => x.IExternalEdges()).ToList();
@@ -102,38 +108,74 @@ public static List<ICurve> ExternalEdges(this PolySurface surface)
         /**** Public Methods - Mesh                     ****/
         /***************************************************/
 
-        public static List<Line> ExternalEdges(this Mesh mesh)
+        [PreviousVersion("6.0", "BH.Engine.Geometry.Query.ExternalEdges(BH.oM.Geometry.Mesh)")]
+        [Description("Gets the external edge curves of a mesh as a set of lines. Extraction is done by finding all unique edges in the mesh.")]
+        [Input("mesh", "The mesh to extract external edge curves from.")]
+        [Input("filterByTopology", "If true, edges with unique topology are returned. If false, edges with unique geometry is returned. Toggle only renders different result for meshes with duplicate nodes.")]
+        [Input("tolerance", "Tolerance to be used for identifying duplicate edges. Only used if filterByTopology is false.")]
+        [Output("edges", "The external edge curves of the mesh.")]
+        public static List<Line> ExternalEdges(this Mesh mesh, bool filterByTopology = false, double tolerance = Tolerance.Distance)
         {
             if (mesh == null)
                 return null;
 
             if (mesh.Faces.Count < 1)
                 return null;
 
-            List<Line> edges = mesh.Faces.SelectMany(f => f.Edges(mesh)).ToList();
+            if (filterByTopology)
+            {
+                List<Tuple<int, int>> allEdgeTopologies = new List<Tuple<int, int>>();
+
+                //Creates tuples of indecies of edges of each face, ordering the index order so the lowest number is always first (to simplify grouping lower down)
+                foreach (Face face in mesh.Faces)
+                {
+                    allEdgeTopologies.Add(new Tuple<int, int>(Math.Min(face.A, face.B), Math.Max(face.A, face.B)));
+                    allEdgeTopologies.Add(new Tuple<int, int>(Math.Min(face.B, face.C), Math.Max(face.B, face.C)));
+                    if (face.D == -1)
+                    {
+                        allEdgeTopologies.Add(new Tuple<int, int>(Math.Min(face.C, face.A), Math.Max(face.C, face.A)));
+                    }
+                    else
+                    {
+                        allEdgeTopologies.Add(new Tuple<int, int>(Math.Min(face.C, face.D), Math.Max(face.C, face.D)));
+                        allEdgeTopologies.Add(new Tuple<int, int>(Math.Min(face.D, face.A), Math.Max(face.D, face.A)));
+                    }
+                }
+
+                IEnumerable<Tuple<int, int>> unique = allEdgeTopologies.GroupBy(x => x).Where(x => x.Count() == 1).SelectMany(x => x);  //Get out instances that are uniqe
 
-            for (int i = edges.Count - 1; i > 0; i--)
+                return unique.Select(x => new Line { Start = mesh.Vertices[x.Item1], End = mesh.Vertices[x.Item2] }).ToList(); //Generate lines based on the unique tuples
+            }
+            else
             {
-                for (int n = i - 1; n >= 0; n--)
+                List<Line> edges = mesh.Faces.SelectMany(f => f.Edges(mesh)).ToList();
+
+                double sqTol = tolerance * tolerance;
+
+                for (int i = edges.Count - 1; i > 0; i--)
                 {
-                    if ((edges[i].Start == edges[n].Start & edges[i].End == edges[n].End) | // edge[i] == edge[n]
-                        (edges[i].Start == edges[n].End & edges[i].End == edges[n].Start))   // edge[i] == edge[n].Reverse()
+                    for (int n = i - 1; n >= 0; n--)
                     {
-                        edges.RemoveAt(i); // shared edge so remove both
-                        edges.RemoveAt(n);
-                        i--;
-                        break;
+                        if ((edges[i].Start.SquareDistance(edges[n].Start) < sqTol && edges[i].End.SquareDistance(edges[n].End) < sqTol) || // edge[i] == edge[n]
+                            (edges[i].Start.SquareDistance(edges[n].End) < sqTol && edges[i].End.SquareDistance(edges[n].Start) < sqTol))   // edge[i] == edge[n].Reverse()
+                        {
+                            edges.RemoveAt(i); // shared edge so remove both
+                            edges.RemoveAt(n);
+                            i--;
+                            break;
+                        }
                     }
                 }
+                return edges;
             }
-            return edges;
         }
 
 
         /***************************************************/
         /**** Public Methods - Interfaces               ****/
         /***************************************************/
 
+        [Description("Gets the external edge curves of the ISurface.")]
         public static List<ICurve> IExternalEdges(this ISurface surface)
         {
             return ExternalEdges(surface as dynamic);