Topic: equivelent of lisp Osnap function in .net?

[jmaeding]

I use the osnap function a lot in lisp.  It fills a critical need for picking nested entities.
If I want to get the ends of, say, a nested line, I would do this:
(SETQ PT (CADR (ENTSEL "Pick the Line")))
(SETQ SP (OSNAP PT "qui,end")
          MP (OSNAP PT "qui,mid")
          EP (POLAR MP (ANGLE SP MP) (DISTANCE SP MP))
)

Now, this might seem junky, but its actually super efficient and dependable, rather than deal with getting actual data, then translating by xref rotation, scale, mirror and so on.
Is there a function on .net to do this?
I looked in the object browser but did not see anything for it.  It may be right in front of me though...
thanks

[MickD]

Have a look at GetObjectSnapPoints() in the managed arx reference help, all drawn autocad entities have this property and using this api you have direct access to them.
hth.

[jmaeding]

ah, exactly the info I wanted - the answer and how to research it next time, thanks a bunch

[Jeff Moran]

Have a look at GetObjectSnapPoints() in the managed arx reference help, all drawn autocad entities have this property and using this api you have direct access to them.
hth.

Mick,

Would you happen to have an example for GetObjectSnapPoints(). I'm having a little trouble understanding how to implement this API.

Thanks
Jeff

[MickD]

Sorry Jeff, I don't but James may have coded something up he can share.

In the mean time I would suggest looking into the ARX ref.-> AcDb -> AcDbEntity-> getOsnapPoints() method which explains how and what the parameters are used for (the managed method simply wraps this so it should be very similar).
While the managed help does list all/most methods available they have little help in the way of using them and I guess they expect you to be able to understand the C/C++ help already available.

cheers.

[Jeff Moran]

Sorry Jeff, I don't but James may have coded something up he can share.

In the mean time I would suggest looking into the ARX ref.-> AcDb -> AcDbEntity-> getOsnapPoints() method which explains how and what the parameters are used for (the managed method simply wraps this so it should be very similar).
While the managed help does list all/most methods available they have little help in the way of using them and I guess they expect you to be able to understand the C/C++ help already available.

cheers.

Thanks Mick,

I did find an example from someone in the .net discussion group in which the person was having a problem. When I tried the example I keep getting an error.
the example:  ent.GetObjectSnapPoints(ObjectSnapModes.ModeMid, 0, pickPt, pickPt, Matrix3d.Identity, snapPts, geomIds);
I believe my problem was with the Matrix3d.Identy part. But I'm not sure.

Thanks for you help though, I did look into the c++ code and found it a little more helpful, but I'm not quite there yet.
Jeff

[Jeff Moran]

Sorry Jeff, I don't but James may have coded something up he can share.

cheers.

James,

If your there! I would like to know if you had any luck!

Thanks
Jeff

[MickD]

it looks like you are passing in the matrix identity 'property', you need to pass it a matrix set to the current view matrix but if you are not in a custom view (ie. you're working in 2d in wcs plan view), setting your matrix to identity should be fine.

Matrix3d mat = new Matrix3d();
mat = Matrix3d.Identity();
ent.GetObjectSnapPoints(ObjectSnapModes.ModeMid, 0, pickPt, pickPt, mat, snapPts, geomIds);

or something like that, it's been a while

[Jeff Moran]

Matrix3d mat = new Matrix3d();
mat = Matrix3d.Identity();
ent.GetObjectSnapPoints(ObjectSnapModes.ModeMid, 0, pickPt, pickPt, mat, snapPts, geomIds);

I gave it a try, and I'm still getting an error. It says "eInvalidInput", but it doesn't tell me what input is Invalid!

[Jeff Moran]

I figured it out!
I used a 1 instead of a 0
ent.GetObjectSnapPoints(ObjectSnapModes.ModeMid, 0, pickPt, pickPt, mat, snapPts, geomIds);
changed to
ent.GetObjectSnapPoints(ObjectSnapModes.ModeMid, 1, pickPt, pickPt, mat, snapPts, geomIds);

[MickD]

could you post the section of code (ie the whole method) to have a look at, someone will be able to spot something a bit quicker that way, thanks.

good news!

[Kerry]

James, Jeff.

Any code and explanation notes you are able post will be a great help for anyone following this thread (now and in the future)


ps:
Welcome to theSwamp Jeff !
Great to see another adventurer posting here.

[Jeff Moran]

ps:
Welcome to theSwamp Jeff !
Great to see another adventurer posting here.

Thanks for the nice welcome Kerry,

I'm a independent consultant for Architects and Structural Engineers. I've written many lisp programs over the years and wanted to expand my level of experience to learning .net using C#. I thought the best way I could get a good start would be to convert my lisp programs to C#.

The lisp to .net program I'm working on is one for Structural where you add text(beam size) to a line (beam). The line can be just about anything that can accept a mid point snap and an end  point snap. ie: polyline, block, xref, arc, etc.

Here are both my lisp and my C# in progress:

Lisp Code:

Code: [Select]

(defun Initialize ()
(setq NewLayer "ANNO-NOTE")
(if (null (tblsearch "LAYER" NewLayer))
    (command "._layer" "new" NewLayer "s" NewLayer "C" "2" NewLayer "")
);End if

(command "._layer" "s" "ANNO-NOTE" "")
(command "COLOR" "BYLAYER")
 
(setq OldSnapMode (getvar "OSMODE"))
(SETVAR "OSMODE" 0)
 
(setq DwgScale (/ 1.0 (getvar "CANNOSCALEVALUE")))
 
(setq Entity (nentsel))
(setq EndPoint (osnap (cadr Entity) "End"))
(setq MidPoint (osnap (cadr Entity) "mid"))
 
(setq LineAngle (rtd (angle EndPoint MidPoint)))

;Adjust Angle for proper text orientation
(if
  (and
  (> LineAngle 90.1)
  (< LineAngle 270.1)
  )
  (setq LineAngle (- LineAngle 180))
 );end if
 
);END DEFUN
 

(defun c:BMX (/ NewLayer OldSnapMode Entity EndPoint MidPoint LineAngle DwgScale TextPoint)
(Initialize)
(setq TextPoint (Polar MidPoint (dtr (+ LineAngle 90)) (* 0.03125 DwgScale)))
(initdia)
(command "._MText" TextPoint "J" "BC" "R" LineAngle "W" "0")
(SETVAR "OSMODE" OldSnapMode)
);End defun

(defun c:UBMX (/ NewLayer OldSnapMode Entity EndPoint MidPoint LineAngle DwgScale TextPoint)
(Initialize)
(setq TextPoint (Polar MidPoint (dtr (+ LineAngle 270)) (* 0.03125 DwgScale)))
(initdia)
(command "._MText" TextPoint "J" "TC" "R" LineAngle "W" "0")
(SETVAR "OSMODE" OldSnapMode)
);End defun

C# code:

Code: [Select]

        [CommandMethod("BeaMtext")]
        public void AddBeamText()
        {
            Editor ed = Application.DocumentManager.MdiActiveDocument.Editor;
            Database db = HostApplicationServices.WorkingDatabase;
            Transaction tr = db.TransactionManager.StartTransaction();

            PromptEntityResult selectionRes = ed.GetEntity("Select Entity ");

            if (selectionRes.Status == PromptStatus.OK)   
            {
                try
                {
                    ObjectId objId = selectionRes.ObjectId;
                    Entity ent = (Entity)tr.GetObject(objId, OpenMode.ForRead);

                    Point3d pickPt = selectionRes.PickedPoint;
                    Matrix3d mat = new Matrix3d();
                    mat = Matrix3d.Identity;
                    Point3dCollection snapPts = new Point3dCollection();
                    IntegerCollection geomIds = new IntegerCollection();
                    geomIds.Add(0);

                    ent.GetObjectSnapPoints(ObjectSnapModes.ModeMid, 1, pickPt, pickPt, mat, snapPts, geomIds);
                    ed.WriteMessage("\nYour selected point is:" + pickPt.ToString());
                    ent.Dispose();
                }
                catch (Autodesk.AutoCAD.Runtime.Exception ex)
                {
                    ed.WriteMessage(ex.Message);
                    tr.Abort();
                }
               
            }//end if
        }//end function


[Jeff Moran]

I finally stumbled on what I wanted all along, and it's a lot less complex than I thought.
I believe the equivalent code for this lisp:

(setq Entity (entsel))
(setq MidPoint (osnap (cadr Entity) "mid"))

is

PromptEntityResult selectionRes = ed.GetEntity("Select Entity ");
Point3d pickPt = selectionRes.PickedPoint;
Point3d snapPt = ed.Snap("midpoint", pickPt);

[sinc]

Just be aware that is really risky code.

All you are doing is mimicking what happens when the user clicks on that point, and has the MID osnap turned on.

If entities overlap at that point, you may not get the midpoint of the previously-selected entity.  You may get the midpoint of a different entity.