createblock

          
using Rhino.DocObjects;

partial class Examples
{
  public static Rhino.Commands.Result CreateBlock(Rhino.RhinoDoc doc)
  {
    // Select objects to define block
    var go = new Rhino.Input.Custom.GetObject();
    go.SetCommandPrompt( "Select objects to define block" );
    go.ReferenceObjectSelect = false;
    go.SubObjectSelect = false;
    go.GroupSelect = true;

    // Phantoms, grips, lights, etc., cannot be in blocks.
    const ObjectType forbidden_geometry_filter = Rhino.DocObjects.ObjectType.Light |
                                                 Rhino.DocObjects.ObjectType.Grip | Rhino.DocObjects.ObjectType.Phantom;
    const ObjectType geometry_filter = forbidden_geometry_filter ^ Rhino.DocObjects.ObjectType.AnyObject;
    go.GeometryFilter = geometry_filter;
    go.GetMultiple(1, 0);
    if (go.CommandResult() != Rhino.Commands.Result.Success)
      return go.CommandResult();

    // Block base point
    Rhino.Geometry.Point3d base_point;
    var rc = Rhino.Input.RhinoGet.GetPoint("Block base point", false, out base_point);
    if (rc != Rhino.Commands.Result.Success)
      return rc;

    // Block definition name
    string idef_name = "";
    rc = Rhino.Input.RhinoGet.GetString("Block definition name", false, ref idef_name);
    if (rc != Rhino.Commands.Result.Success)
      return rc;
    // Validate block name
    idef_name = idef_name.Trim();
    if (string.IsNullOrEmpty(idef_name))
      return Rhino.Commands.Result.Nothing;

    // See if block name already exists
    Rhino.DocObjects.InstanceDefinition existing_idef = doc.InstanceDefinitions.Find(idef_name, true);
    if (existing_idef != null)
    {
      Rhino.RhinoApp.WriteLine("Block definition {0} already exists", idef_name);
      return Rhino.Commands.Result.Nothing;
    }

    // Gather all of the selected objects
    var geometry = new System.Collections.Generic.List<Rhino.Geometry.GeometryBase>();
    var attributes = new System.Collections.Generic.List<Rhino.DocObjects.ObjectAttributes>();
    for (int i = 0; i < go.ObjectCount; i++)
    {
      var rhinoObject = go.Object(i).Object();
      if (rhinoObject != null)
      {
        geometry.Add(rhinoObject.Geometry);
        attributes.Add(rhinoObject.Attributes);
      }
    }

    // Gather all of the selected objects
    int idef_index = doc.InstanceDefinitions.Add(idef_name, string.Empty, base_point, geometry, attributes);

    if( idef_index < 0 )
    {
      Rhino.RhinoApp.WriteLine("Unable to create block definition", idef_name);
      return Rhino.Commands.Result.Failure;
    }
    return Rhino.Commands.Result.Failure;
  }
}