Chamfering the selected edge of an AutoCAD solid using .NET

Another piece of code culled from an email from Balaji Ramamoorthy, from DevTech India. I did a little refactoring and formatting, to fit the blog. Thanks, Balaji! :-)

The below C# code demonstrates how to use Solid3d.ChamferEdges() with a user-selected edge and face. Balaji has also provided code to determine the edge and face programmatically – without the user needing to select anything – using the Brep API. I expect to show that approach in a subsequent post.

using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.EditorInput;
using Autodesk.AutoCAD.Runtime;
using System;
 
namespace SolidEditing
{
  public class Commands
  {
    [CommandMethod("EC")]
    public void EdgeChamfer()
    {
      Document doc =
        Application.DocumentManager.MdiActiveDocument;
      Database db = doc.Database;
      Editor ed = doc.Editor;
 
      // Select an edge
 
      PromptSelectionOptions pso =
        new PromptSelectionOptions();
      pso.MessageForAdding = "\nSelect edge to chamfer";
      pso.SingleOnly = true;
      pso.ForceSubSelections = true;
 
      PromptSelectionResult psrEdge = ed.GetSelection(pso);
 
      if (psrEdge.Status != PromptStatus.OK)
        return;
 
      // Select a face
 
      pso.MessageForAdding =
        "\nSelect the face to which the edge belongs";
      pso.SinglePickInSpace = true;
 
      PromptSelectionResult psrFace = ed.GetSelection(pso);
 
      if (psrFace.Status != PromptStatus.OK)
        return;
 
      try
      {
        Transaction tr =
          db.TransactionManager.StartTransaction();
        using (tr)
        {
          ObjectId edgeSolId, faceSolId;
 
          // Get the subentity Id for the edge and the face
 
          SubentityId edgeId =
            GetSubentity(
              ed, tr, psrEdge.Value, SubentityType.Edge,
              out edgeSolId
            );
 
          SubentityId faceId =
            GetSubentity(
              ed, tr, psrFace.Value, SubentityType.Face,
              out faceSolId
            );
 
          // We also have the Ids of their containing solids,
          // so we can check they belong to the same one
 
          if (edgeSolId == faceSolId && edgeSolId != ObjectId.Null)
          {
            Solid3d solid =
              tr.GetObject(edgeSolId, OpenMode.ForWrite)
              as Solid3d;
            if (solid != null)
            {
              // Here's where we actually chamfer the edge
              // with hard-coded values
 
              SubentityId[] edgeIds =
                new SubentityId[] { edgeId };
              solid.ChamferEdges(edgeIds, faceId, 0.5, 1.0);
            }
            tr.Commit();
          }
        }
      }
      catch (Autodesk.AutoCAD.Runtime.Exception ex)
      {
        ed.WriteMessage(ex.Message);
      }
    }
 
    public static SubentityId GetSubentity(
      Editor ed, Transaction tr, SelectionSet ss,
      SubentityType type, out ObjectId solId
    )
    {
      SubentityId retId = new SubentityId();
 
      // Should have only one object in the array
 
      SelectedObject so = ss[0];
 
      // We set our out parameter to the owning solid's ObjectId
 
      solId = so.ObjectId;
 
      // Access the solid via the transaction passed in
 
      Solid3d solid =
        tr.GetObject(so.ObjectId, OpenMode.ForRead)
        as Solid3d;
 
      // Get its subentities
 
      SelectedSubObject[] sso = so.GetSubentities();
 
      // Get their first subentity's type
 
      SubentityType subentityType =
        sso[0].FullSubentityPath.SubentId.Type;
 
      // See if it's of the type we want
 
      if (subentityType == type)
      {
        retId = sso[0].FullSubentityPath.SubentId;
      }
      else
      {
        ed.WriteMessage(
          "\nInvalid Subentity Type: {0}, " +
          "Expecting a {1} to be selected.\n",
          subentityType, type.ToString()
        );
      }
 
      return retId;
    }
  }
}