It’s quite common for AutoCAD developers to use Extended Entity Data (XData) to tag objects their application cares about. This is certainly the approach taken in the recent series showing how to overrule the graphics display for an object – we store a “pipe radius” in XData attached to the Line or Circle we want to have a 3D profile.
That’s fine, but what if we’re storing a unique identifier with an object in XData that we do not want copied with the object? The Overrule API in AutoCAD 2010 allows you to hook into the DeepClone of an object and control what data gets copied with the object, whether via the COPY command or some other process that chooses to copy your object.
Here’s an example CopyOverrule class that makes use of the XData functions we previously defined as part of the PipeDrawOverrule class:
public class CopyOverrule : ObjectOverrule
{
static public CopyOverrule theOverrule =
new CopyOverrule();
public override DBObject DeepClone(
DBObject dbObject, DBObject ownerObject,
IdMapping idMap, bool isPrimary
)
{
// First we deep clone the object via the parent
DBObject res =
base.DeepClone(dbObject, ownerObject, idMap, isPrimary);
// Then we check for our XData
if (PipeDrawOverrule.PipeRadiusForObject(res) > 0.0)
{
// A transaction is needed by the set function to access
// the RegApp table - we could also assume the app name
// is registered and have a separate implementation
// not taking the transaction...
// Just as we might also have chosen to remove the XData
Transaction tr =
dbObject.Database.TransactionManager.StartTransaction();
using (tr)
{
PipeDrawOverrule.SetPipeRadiusOnObject(tr, res, 0.0);
tr.Commit();
}
}
return res;
}
}
In this code we call the DeepClone implementation in the parent class and set the result – the copy of our object – to the res variable. If there any additional objects were copied during the DeepClone process, there should be IdPair entries in the idMap variable referring to both the originator and the copy. In this code we just check the XData on the returned object, but we might also iterate through and check the contents of the idMap.
Also, rather than removing the XData – which some people might prefer to do, depending on the behaviour of their application – we just set it to 0. Which is enough to make sure the object’s graphic display doesn’t make use of a pipe radius.
Here’s the complete code, including the code to register and unregister the overrule in the OVERRULE0 and OVERRULE1 commands:
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.EditorInput;
using Autodesk.AutoCAD.Geometry;
using Autodesk.AutoCAD.GraphicsInterface;
using Autodesk.AutoCAD.Colors;
namespace DrawOverrules
{
public abstract class PipeDrawOverrule : DrawableOverrule
{
const string regAppName = "TTIF_PIPE";
public PipeDrawOverrule()
{
// Tell AutoCAD to filter on our application name
// (this means our overrule will only be called
// on objects possessing XData with this name)
SetXDataFilter(regAppName);
}
// Get the XData for a particular object
// and return the "pipe radius" if it exists
public static double PipeRadiusForObject(DBObject obj)
{
double res = 0.0;
ResultBuffer rb = obj.XData;
if (rb != null)
{
bool foundStart = false;
foreach (TypedValue tv in rb)
{
if (tv.TypeCode == (int)DxfCode.ExtendedDataRegAppName &&
tv.Value.ToString() == regAppName)
foundStart = true;
else
{
if (foundStart == true)
{
if (tv.TypeCode == (int)DxfCode.ExtendedDataReal)
{
res = (double)tv.Value;
break;
}
}
}
}
rb.Dispose();
}
return res;
}
// Set the "pipe radius" in the XData of a particular object
public static void SetPipeRadiusOnObject(
Transaction tr, DBObject obj, double radius
)
{
Database db = obj.Database;
// Make sure the application is registered
// (we could separate this out to be called
// only once for a set of operations)
RegAppTable rat =
(RegAppTable)tr.GetObject(
db.RegAppTableId,
OpenMode.ForRead
);
if (!rat.Has(regAppName))
{
rat.UpgradeOpen();
RegAppTableRecord ratr = new RegAppTableRecord();
ratr.Name = regAppName;
rat.Add(ratr);
tr.AddNewlyCreatedDBObject(ratr, true);
}
// Create the XData and set it on the object
ResultBuffer rb =
new ResultBuffer(
new TypedValue(
(int)DxfCode.ExtendedDataRegAppName, regAppName
),
new TypedValue(
(int)DxfCode.ExtendedDataReal, radius
)
);
obj.XData = rb;
rb.Dispose();
}
}
// An overrule to make a pipe out of line
public class LinePipeDrawOverrule : PipeDrawOverrule
{
static public LinePipeDrawOverrule theOverrule =
new LinePipeDrawOverrule();
private SweepOptions sweepOpts = new SweepOptions();
public override bool WorldDraw(Drawable d, WorldDraw wd)
{
double radius = 0.0;
if (d is DBObject)
radius = PipeRadiusForObject((DBObject)d);
if (radius > 0.0)
{
Line line = d as Line;
if (line != null)
{
// Draw the line as is, with overruled attributes
base.WorldDraw(line, wd);
if (!line.Id.IsNull && line.Length > 0.0)
{
// Draw a pipe around the line
EntityColor c =
wd.SubEntityTraits.TrueColor;
wd.SubEntityTraits.TrueColor =
new EntityColor(0x00AfAfff);
wd.SubEntityTraits.LineWeight =
LineWeight.LineWeight000;
Circle clr =
new Circle(
line.StartPoint,
line.EndPoint - line.StartPoint,
radius
);
ExtrudedSurface pipe = new ExtrudedSurface();
try
{
pipe.CreateExtrudedSurface(
clr, line.EndPoint - line.StartPoint, sweepOpts
);
}
catch
{
Document doc =
Application.DocumentManager.MdiActiveDocument;
doc.Editor.WriteMessage(
"\nFailed with CreateExtrudedSurface."
);
}
clr.Dispose();
pipe.WorldDraw(wd);
pipe.Dispose();
wd.SubEntityTraits.TrueColor = c;
}
return true;
}
}
return base.WorldDraw(d, wd);
}
public override int SetAttributes(Drawable d, DrawableTraits t)
{
int b = base.SetAttributes(d, t);
double radius = 0.0;
if (d is DBObject)
radius = PipeRadiusForObject((DBObject)d);
if (radius > 0.0)
{
// Set color to index 6
t.Color = 6;
// and lineweight to .40 mm
t.LineWeight = LineWeight.LineWeight040;
}
return b;
}
}
// An overrule to make a pipe out of circle
public class CirclePipeDrawOverrule : PipeDrawOverrule
{
static public CirclePipeDrawOverrule theOverrule =
new CirclePipeDrawOverrule();
private SweepOptions sweepOpts = new SweepOptions();
public override bool WorldDraw(Drawable d, WorldDraw wd)
{
double radius = 0.0;
if (d is DBObject)
radius = PipeRadiusForObject((DBObject)d);
if (radius > 0.0)
{
Circle circle = d as Circle;
if (circle != null)
{
// Draw the circle as is, with overruled attributes
base.WorldDraw(circle, wd);
// Needed to avoid ill-formed swept surface
if (circle.Radius > radius)
{
// Draw a pipe around the cirle
EntityColor c = wd.SubEntityTraits.TrueColor;
wd.SubEntityTraits.TrueColor =
new EntityColor(0x3fffe0e0);
wd.SubEntityTraits.LineWeight =
LineWeight.LineWeight000;
Vector3d normal =
(circle.Center - circle.StartPoint).
CrossProduct(circle.Normal);
Circle clr =
new Circle(
circle.StartPoint, normal, radius
);
SweptSurface pipe = new SweptSurface();
pipe.CreateSweptSurface(clr, circle, sweepOpts);
clr.Dispose();
pipe.WorldDraw(wd);
pipe.Dispose();
wd.SubEntityTraits.TrueColor = c;
}
return true;
}
}
return base.WorldDraw(d, wd);
}
public override int SetAttributes(Drawable d, DrawableTraits t)
{
int b = base.SetAttributes(d, t);
double radius = 0.0;
if (d is DBObject)
radius = PipeRadiusForObject((DBObject)d);
if (radius > 0.0)
{
// Set color to index 2
t.Color = 2;
// and lineweight to .60 mm
t.LineWeight = LineWeight.LineWeight060;
}
return b;
}
}
public class LinePipeTransformOverrule : TransformOverrule
{
static public LinePipeTransformOverrule theOverrule =
new LinePipeTransformOverrule();
private SweepOptions sweepOpts = new SweepOptions();
public override void Explode(Entity e, DBObjectCollection objs)
{
double radius = 0.0;
if (e is DBObject)
radius = PipeDrawOverrule.PipeRadiusForObject(e);
if (radius > 0.0)
{
Line line = e as Line;
if (line != null)
{
if (!line.Id.IsNull && line.Length > 0.0)
{
// Draw a pipe around the line
Circle clr =
new Circle(
line.StartPoint,
line.EndPoint - line.StartPoint,
radius
);
ExtrudedSurface pipe = new ExtrudedSurface();
try
{
pipe.CreateExtrudedSurface(
clr, line.EndPoint - line.StartPoint, sweepOpts
);
}
catch
{
Document doc =
Application.DocumentManager.MdiActiveDocument;
doc.Editor.WriteMessage(
"\nFailed with CreateExtrudedSurface."
);
}
clr.Dispose();
objs.Add(pipe);
}
return;
}
}
base.Explode(e, objs);
}
}
public class CirclePipeTransformOverrule : TransformOverrule
{
static public CirclePipeTransformOverrule theOverrule =
new CirclePipeTransformOverrule();
private SweepOptions sweepOpts = new SweepOptions();
public override void Explode(Entity e, DBObjectCollection objs)
{
double radius = 0.0;
if (e is DBObject)
radius = PipeDrawOverrule.PipeRadiusForObject(e);
if (radius > 0.0)
{
Circle circle = e as Circle;
if (circle != null)
{
// Needed to avoid ill-formed swept surface
if (circle.Radius > radius)
{
// Draw a pipe around the cirle
Vector3d normal =
(circle.Center - circle.StartPoint).
CrossProduct(circle.Normal);
Circle clr =
new Circle(
circle.StartPoint, normal, radius
);
SweptSurface pipe = new SweptSurface();
pipe.CreateSweptSurface(clr, circle, sweepOpts);
clr.Dispose();
objs.Add(pipe);
}
return;
}
}
base.Explode(e, objs);
}
}
public class CopyOverrule : ObjectOverrule
{
static public CopyOverrule theOverrule =
new CopyOverrule();
public override DBObject DeepClone(
DBObject dbObject, DBObject ownerObject,
IdMapping idMap, bool isPrimary
)
{
// First we deep clone the object via the parent
DBObject res =
base.DeepClone(dbObject, ownerObject, idMap, isPrimary);
// Then we check for our XData
if (PipeDrawOverrule.PipeRadiusForObject(res) > 0.0)
{
// A transaction is needed by the set function to access
// the RegApp table - we could also assume the app name
// is registered and have a separate implementation
// not taking the transaction...
// Just as we might also have chosen to remove the XData
Transaction tr =
dbObject.Database.TransactionManager.StartTransaction();
using (tr)
{
PipeDrawOverrule.SetPipeRadiusOnObject(tr, res, 0.0);
tr.Commit();
}
}
return res;
}
}
public class Commands
{
private double _radius = 0.0;
public void Overrule(bool enable)
{
// Regen to see the effect
// (turn on/off Overruling and LWDISPLAY)
DrawableOverrule.Overruling = enable;
if (enable)
Application.SetSystemVariable("LWDISPLAY", 1);
else
Application.SetSystemVariable("LWDISPLAY", 0);
Document doc =
Application.DocumentManager.MdiActiveDocument;
doc.SendStringToExecute("REGEN3\n", true, false, false);
doc.Editor.Regen();
}
[CommandMethod("OVERRULE1")]
public void OverruleStart()
{
ObjectOverrule.AddOverrule(
RXClass.GetClass(typeof(Line)),
LinePipeDrawOverrule.theOverrule,
true
);
ObjectOverrule.AddOverrule(
RXClass.GetClass(typeof(Circle)),
CirclePipeDrawOverrule.theOverrule,
true
);
ObjectOverrule.AddOverrule(
RXClass.GetClass(typeof(Line)),
LinePipeTransformOverrule.theOverrule,
true
);
ObjectOverrule.AddOverrule(
RXClass.GetClass(typeof(Circle)),
CirclePipeTransformOverrule.theOverrule,
true
);
ObjectOverrule.AddOverrule(
RXClass.GetClass(typeof(Entity)),
CopyOverrule.theOverrule,
true
);
Overrule(true);
}
[CommandMethod("OVERRULE0")]
public void OverruleEnd()
{
ObjectOverrule.RemoveOverrule(
RXClass.GetClass(typeof(Line)),
LinePipeDrawOverrule.theOverrule
);
ObjectOverrule.RemoveOverrule(
RXClass.GetClass(typeof(Circle)),
CirclePipeDrawOverrule.theOverrule
);
ObjectOverrule.RemoveOverrule(
RXClass.GetClass(typeof(Line)),
LinePipeTransformOverrule.theOverrule
);
ObjectOverrule.RemoveOverrule(
RXClass.GetClass(typeof(Circle)),
CirclePipeTransformOverrule.theOverrule
);
ObjectOverrule.RemoveOverrule(
RXClass.GetClass(typeof(Entity)),
CopyOverrule.theOverrule
);
Overrule(false);
}
[CommandMethod("MP", CommandFlags.UsePickSet)]
public void MakePipe()
{
Document doc =
Application.DocumentManager.MdiActiveDocument;
Database db = doc.Database;
Editor ed = doc.Editor;
// Ask the user to select the entities to make into pipes
PromptSelectionOptions pso =
new PromptSelectionOptions();
pso.AllowDuplicates = false;
pso.MessageForAdding =
"\nSelect objects to turn into pipes: ";
PromptSelectionResult selRes =
doc.Editor.GetSelection(pso);
// If the user didn't make valid selection, we return
if (selRes.Status != PromptStatus.OK)
return;
SelectionSet ss = selRes.Value;
// Ask the user for the pipe radius to set
PromptDoubleOptions pdo =
new PromptDoubleOptions(
"\nSpecify pipe radius:"
);
// Use the previous value, if if already called
if (_radius > 0.0)
{
pdo.DefaultValue = _radius;
pdo.UseDefaultValue = true;
}
pdo.AllowNegative = false;
pdo.AllowZero = false;
PromptDoubleResult pdr =
ed.GetDouble(pdo);
// Return if something went wrong
if (pdr.Status != PromptStatus.OK)
return;
// Set the "last radius" value for when
// the command is called next
_radius = pdr.Value;
// Use a transaction to edit our various objects
Transaction tr =
db.TransactionManager.StartTransaction();
using (tr)
{
// Loop through the selected objects
foreach (SelectedObject o in ss)
{
// We could choose only to add XData to the objects
// we know will use it (Lines and Circles, for now)
DBObject obj =
tr.GetObject(o.ObjectId, OpenMode.ForWrite);
PipeDrawOverrule.SetPipeRadiusOnObject(tr, obj, _radius);
}
tr.Commit();
}
}
}
}
Let’s see what happens when we attempt to copy a circular pipe using the standard COPY command (after having first created it using MP and have it display using OVERRULE1). We can see that as we select the location, the circle is displayed with a pipe radius:
But once we specify the location, the circle’s radius is removed:
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