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AU Handouts: There's More to .DWG Than AutoCAD® - Part 1
[As mentioned in the last post, I'll be publishing chunks of the handouts for my AU classes via this blog over the coming weeks]
Introduction
This session focuses on downstream technologies that can be used to access DWG content outside of AutoCAD-based products. We’re going to start by creating a basic model inside AutoCAD comprised of 3D solid objects, and then look at a simple AutoCAD .NET application to access information about those solids. We will then take the same code and build a non-graphical (in terms of geometry - it does, after all, have a GUI) application around it using Autodesk RealDWG. Later on we’ll look at the same code running inside a custom-branded design application built using AutoCAD OEM.
We will also spend time looking at DWG TrueView and the DWG HOOPS viewer, to understand how they might be used to enhance the graphical display of DWGs without the editing overhead introduced with AutoCAD-based products.
Firstly, why are we using 3D solids in this example? The choice was somewhat arbitrary – the point is really to demonstrate the ability to access properties of objects stored in a DWG file without AutoCAD running – but it does suit our overall purpose for a few reasons:
- As 3D entities, 3D solids allow us to evaluate the 3D capabilities of the viewing technologies we’re looking at.
- They provide precise data that is of interest to us – in this case we’re going to mine their volume – and can also have data attached of a less precision-oriented nature, such as materials.
- Regarding both the above points, they also feed into the fact that this demo continues in another AU session, “DE401-2: Enriching Your DWF™”, which focuses on working with DWF data that is published from AutoCAD. In that session we’ll look at how to harness both 2D and 3D data to implement rich applications focused on published – rather than native – data.
A quick word on the programming technology used in this demonstration. The code samples are all in VB.NET: regular readers of my blog (http://blogs.autodesk.com/through-the-interface) will know I have a preference for C#, having spent years working with C++, but I’m sticking with VB.NET for this demonstration: we originally developed the material using VB.NET to reach the broader audience of Visual Basic professionals.
These handouts, along with the sample projects demonstrated within them, have been posted to my blog: http://blogs.autodesk.com/through-the-interface. Only significant portions of code will be highlighted in this document, and even those should not need to be typed back in. :-)
[You can download the source used in this demo from here for the AutoCAD application and here for the RealDWG application.]
Create a simple 3D model in AutoCAD and access it using .NET
There are various 3D modeling commands available in AutoCAD, of which detailed review is outside the scope of this session. We simply want to populate a model with a number of 3D solids with materials attached. Here’s the kind of thing we’re looking for:
Figure 1 – a simple set of 3D solids inside AutoCAD
Now we’re ready to start looking at the code we’ll use inside an AutoCAD application, as well as within RealDWG and AutoCAD OEM, to access the information in this model.
Here’s code from a file called SolidInfo.vb to represent a data structure we’ll use to collect information about our 3D solids – their type, location, ID (the AutoCAD handle) and volume.
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry
Imports Autodesk.AutoCAD.Interop
Imports Autodesk.AutoCAD.Interop.Common
Imports System.Math
' The SolidData class encapsulates the data we
' want to collect and display for Solid3d objects
Public Class SolidData
' We care about Type, Location, ID & Volume
Private m_Type As String
Private m_Location As String
Private m_Id As String
Private m_Volume As Double
Public Property Type()
Get
Return m_Type
End Get
Set(ByVal value)
m_Type = value
End Set
End Property
Public Property Location()
Get
Return m_Location
End Get
Set(ByVal value)
m_Location = value
End Set
End Property
Public Property Id()
Get
Return m_Id
End Get
Set(ByVal value)
m_Id = value
End Set
End Property
Public Property Volume()
Get
Return m_Volume
End Get
Set(ByVal value)
m_Volume = value
End Set
End Property
End Class
' The SolidList class is simply a list of SolidData
' (used when defining the data a grid is bound to)
Public Class SolidList
Inherits System.ComponentModel.BindingList(Of SolidData)
End Class
Now we have a function that will take a database and iterate through its contents, collecting information about 3D solid objects and adding them to a Data-Bound Grid passed in as the second argument. This grid should be created in the UI to be bound to objects of type SolidList (defined above).
Public Module SolidFunctions
' This function will get SolidData for each Solid3d
' in a Database and add them to a BindingSource (a grid
' in a form, typically). It also returns the total volume
' of Solid3ds in the Database
Public Function AnalyzeDatabase _
(ByVal db As Database, _
ByRef sl As System.Windows.Forms.BindingSource) _
As Double
' We will return the total volume of solids
' in the modelspace of this Database
Dim vol As Double = 0
sl.Clear()
Dim tr As Transaction = _
db.TransactionManager.StartTransaction()
Using tr
Try
Dim bt As BlockTable = _
tr.GetObject _
(db.BlockTableId(), _
OpenMode.ForRead)
Dim btr As BlockTableRecord = _
tr.GetObject _
(bt(BlockTableRecord.ModelSpace), _
OpenMode.ForRead)
' Loop for each entity in the modelspace
For Each entId As ObjectId In btr
Dim ent As Entity = _
tr.GetObject(entId, OpenMode.ForRead)
' If it's a solid, then gather its data
If TypeOf (ent) Is Solid3d Then
Dim solid As Solid3d = CType(ent, Solid3d)
Dim mp As Solid3dMassProperties = _
solid.MassProperties()
Dim sd As New SolidData
' Use the COM API to access the type string
' (exposed through neither ObjectARX nor .NET)
Dim oSolid As Acad3DSolid
oSolid = CType(solid.AcadObject, Acad3DSolid)
sd.Type = oSolid.SolidType
' Use the centroid for the location
sd.Location = _
Round(mp.Centroid.X, 4).ToString() + ", " + _
Round(mp.Centroid.Y, 4).ToString() + ", " + _
Round(mp.Centroid.Y, 4).ToString()
sd.Id = solid.Handle.ToString
sd.Volume = Round(mp.Volume, 4)
' Add each solid's info to the list
sl.Add(sd)
' And add its volume to the total
vol += sd.Volume()
End If
Next
' Committing is cheaper than aborting,
' even if we didn't change the drawing
tr.Commit()
Catch ex As Exception
MsgBox("Error: " + ex.Message)
End Try
End Using
AnalyzeDatabase = Math.Round(vol, 2)
End Function
End Module
We will now build the code into a complete AutoCAD .NET application which defines two commands – the first, SD, launches a dockable AutoCAD palette listing the 3D solids in our model and totaling their volume, and the second, SD2, does the same from a standard dialog:
Figure 2 - the dialogs displayed by the SD and SD2 custom commands
These two dialogs share a common implementation: they both contain a UserControl that contains a DataGridView and a BindingNavigator to browse the contained records. There’s an optional “Analysis” button in the control, which allows the analysis operation to be launched manually. This is hidden when within the Dialog version, as it was primarily intended as a modal interface which launches the analysis automatically on load.
Build a RealDWG application from the AutoCAD .NET code
Now we will take the basic code from the SolidInfo.vb file and reuse it in a RealDWG application. It is also possible to use the User Control directly (defined in SolidUserControl.vb, SolidUserControl.Designer.vb and SolidUserControl.resx) but I thought it would be of more interest to demonstrate building the steps needed to build a RealDWG application and how it differs from a standard AutoCAD .NET module.
We start by creating a new Windows Application in Visual Studio 2005:
Figure 3 – creating a new project for our RealDWG application
The first step is to copy across the SolidInfo.vb file into our project folder and add it into the project as an existing item. To get the project to build you will need to select two project references: one for the RealDWG managed assembly, and one for the COM type library:
Figure 4 - adding project references to the RealDWG managed assembly & COM type-library
We need the COM type library to work around a specific limitation in the .NET API to AutoCAD and in ObjectARX, its underlying API. These APIs do not provide access to the type of a solid – whether it’s a sphere, a cylinder or a pyramid, for instance – so we need to use COM to retrieve the information.
New VB.NET Windows Application projects contain a default form, Form1.vb. Rename this to MainForm.vb and design a simple user interface with a TextBox for a filename (named DwgFileToAnalyze), a Button to browse to the file (named BrowseButton) and a DataGridView (called whatever you like :-). When you come to adding the DataGridView you will be prompted to define a Data Source. Select “Add a New Data Source” of type “Object”. From here you will be able to browse down to our SolidList class:
Figure 5 – adding a DataGridView and its associated Data Source
Now just add a Label (named TotalVolumeText) at the bottom (going the whole width of the dialog, setting the AutoSize property to “False”, the Font to something nice and visible and TextAlign to “MiddleRight”). You can leave the contents blank, as we’ll be setting those programmatically.
I always like the UI to behave well on resize, even with a sample app, so I’d suggest editing the Anchor property of the GroupBox and the TextBox to “Top, Left, Right”, of the DataGridView to “Top, Bottom, Left, Right”, and of the VolumeText to “Bottom, Left, Right”.
I’d also change the following DataGridView properties: AllowUserToAddRows to “False”, AllowUserTo DeleteRows to “False” and AutoSizeColumnsMode to “Fill”.
The User Interface is now done – we’re ready to flesh out the application functionality to call our AnalyzeDatabase() from SolidInfo.vb.
First we need to implement some code to make our RealDWG application valid. We’ll add a new file called Program.vb and populate it with a base HostApplicationServices object:
Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.DatabaseServices
'<Assembly: SecuredApplication("<Placeholder for the clear text license>", "<Placeholder for the Autodesk encrypted text license>", "<Placeholder for the client encrypted text license>", "<Placeholder for the client public key>")>
<Assembly: SecuredApplication( _
"THIS IS AN OBJECTDBX (TM) VERSION 2007 CLIENT LICENSE FOR THE EXCLUSIVE USE OF Kean Walmsley. YOUR USE OF OBJECTDBX(TM) IS GOVERNED BY THE SOFTWARE LICENSE INCLUDED IN THE PRODUCT. USE OF THIS SOFTWARE IN VIOLATION OF THE SOFTWARE LICENSE IS A VIOLATION OF U.S. AND/OR INTERNATIONAL COPYRIGHT LAWS AND TREATIES AND YOU MAY BE SUBJECT TO CRIMINAL PENALTIES FOR SUCH USE.", _
' Lines deleted - you will need to be a valid RealDWG license holder to get this text
Public Class MyHostApplicationServices
Inherits HostApplicationServices
Public Overrides Function FindFile _
(ByVal fileName As String, _
ByVal database As Database, _
ByVal hint As FindFileHint) _
As String
FindFile = Nothing
End Function
End Class
I've edited the above text to delete my personal RealDWG license keys – you will need to license RealDWG to receive valid license keys of your own for this code to work. The FindFile function is needed to help RealDWG find supporting files such as fonts. As we’re only accessing information about 3D solid objects it is not important for us to implement this completely.
Now we go to the code window for MainForm.vb – either by double-clicking the form, the browse button, or by selecting View Code from the Solution Explorer when right-clicking on the file. We replace the default implementation with the following:
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Runtime
Public Class MainForm
Private Sub MainForm_Load _
(ByVal sender As System.Object, _
ByVal e As System.EventArgs) _
Handles MyBase.Load
' Initialize RealDWG host subsystem
RuntimeSystem.Initialize _
(New MyHostApplicationServices(), 1033)
End Sub
Private Sub BrowseButton_Click _
(ByVal sender As System.Object, _
ByVal e As System.EventArgs) _
Handles BrowseButton.Click
Dim dlg As New System.Windows.Forms.OpenFileDialog()
dlg.InitialDirectory = _
System.Environment.CurrentDirectory
dlg.Filter = _
"DWG files (*.dwg)|*.dwg|All files (*.*)|*.*"
Dim oc As Cursor = Me.Cursor
If dlg.ShowDialog() = Windows.Forms.DialogResult.OK Then
Me.Cursor = Cursors.WaitCursor
DwgFileToAnalyze.Text = dlg.FileName()
Me.Refresh()
End If
If DwgFileToAnalyze.Text <> "" Then
' Let's read the selected DWG
Dim db As Database = _
New Database(False, True)
Using db
db.ReadDwgFile _
(DwgFileToAnalyze.Text, _
IO.FileShare.None, _
False, Nothing)
HostApplicationServices.WorkingDatabase = db
' Analyze it and display the results
Dim vol As Double = _
AnalyzeDatabase(db, SolidListBindingSource)
TotalVolumeText.Text = _
"Total Volume = " + vol.ToString()
Me.Cursor = oc
End Using
End If
End Sub
End Class
Our code is now ready to build. There is, however, one additional step needed for the application to run. When you receive a license key for RealDWG, you should also receive a public license file (client.snk) that needs to be bound to your application. There’s a utility that ships in RealDWG’s Utils folder – bindmgd – which does just that:
bindmgd -b <YourApp>.exe client.snk
Now our application should run. All being well, when we select the DWG file we created earlier, we should now see the grid populated with data extracted from the 3D solids contained within it:
Figure 6 - our RealDWG application accessing the 3D solid data
October 17, 2007 in AutoCAD, AutoCAD .NET, RealDWG, Training, Visual Studio | Permalink | Comments (9) | TrackBack
Updating a specific attribute inside a folder of AutoCAD drawings using RealDWG from .NET
This post finally takes the code last shown in this previous post, migrating it to use RealDWG to update a folder of DWGs without the need for AutoCAD to be installed on the system. A big thanks to Adam Nagy, a member of DevTech working from our Prague office, who turned around my request to convert the code to work with RealDWG in a matter of hours (if not minutes).
Firstly I need to make it clear that this code will not run without both RealDWG installed (I'm using RealDWG 2007, as the file format didn't change between 2007 and 2008) and a "clear text license key" inserted in the code. You'll see some missing lines (lines 9-15), where it needs to be inserted. Once you've licensed RealDWG you can get this key from Autodesk, allowing you to create RealDWG applications using .NET.
Below is the C# code, with the lines that have been added since the previous entry in red. Firstly, a summary of the changes...
There are clearly lines that are no longer needed - these have just been deleted.
In terms of the additional lines: it's a mixture of code that replaces the use of the AutoCAD editor for user-input, with some additional code needed specifically by RealDWG applications.
Lines 22-122 implement the HostApplicationServices class for our application, which RealDWG will call under certain circumstances, such as when it's trying to find particular support files. The FindFile() function has been implemented to search the Windows fonts folder and the RealDWG install folder for any fonts the system needs to adequately load a DWG. You would need to modify the code to point to the folder your application installs fonts into. Additionally I suspect there's work needed to open files that have fonts missing, mapping alternate fonts in their place: this post assumes that the fonts are all available; in a future post we can certainly look at adding support for alternate font mapping.
These fonts are especially important when dealing with alignment of text and attributes. If RealDWG cannot find the fonts on the system, the DWG will be updated with the new text but the attributes will not be positioned correctly (until they are edited in some way inside the AutoCAD editor). This is quite a common issue when developing with RealDWG, but thankfully one that's fairly easy to solve.
Lines 115-145 replace the use of the AutoCAD editor to prompt the user for the important information. In this case we're just using standard console functions for reading/writing data from/to a command window. This is also the reason for lines 174, 197, 208, 223, 233, 243 & 244 changing.
Line 185 sets the working database: this is very important - especially when working with fonts - and without it your attributes will not align properly.
The protocols of the UpdateAttributesInDatabase() and UpdateAttributesInBlock() functions have also been updated to include the static keyword, although I didn't mark those lines in red as they should probably have been static before. :-)
1 using Autodesk.AutoCAD.DatabaseServices;
2 using Autodesk.AutoCAD.Runtime;
3 using System.Reflection;
4 using System.IO;
5 using System;
6
7 [assembly: SecuredApplication(
8 @"THIS IS AN OBJECTDBX (TM) VERSION 2007 CLIENT LICENSE FOR THE EXCLUSIVE USE OF Kean Walmsley. YOUR USE OF OBJECTDBX(TM) IS GOVERNED BY THE SOFTWARE LICENSE INCLUDED IN THE PRODUCT. USE OF THIS SOFTWARE IN VIOLATION OF THE SOFTWARE LICENSE IS A VIOLATION OF U.S. AND/OR INTERNATIONAL COPYRIGHT LAWS AND TREATIES AND YOU MAY BE SUBJECT TO CRIMINAL PENALTIES FOR SUCH USE.",
16
17 namespace AttributeUpdater
18 {
19 class Program
20 {
21 #region RealDWG
22 class MyHost : HostApplicationServices
23 {
24 private string SearchPath(string fileName)
25 {
26 // check if the file is already with full path
27 if (System.IO.File.Exists(fileName))
28 return fileName;
29
30 // check application folder
31 string applicationPath =
32 Path.GetDirectoryName(
33 Assembly.GetExecutingAssembly().Location
34 );
35 if (File.Exists(applicationPath + "\\" + fileName))
36 return applicationPath + "\\" + fileName;
37
38 // search folders in %PATH%
39 string []paths =
40 Environment.GetEnvironmentVariable(
41 "Path").Split(new char[]{';'}
42 );
43 foreach (string path in paths)
44 {
45 // some folders end with \\, some don't
46 string validatedPath
47 = Path.GetFullPath(path + "\\" + fileName);
48 if (File.Exists(validatedPath))
49 return validatedPath;
50 }
51
52 // check the Fonts folders
53 string systemFonts =
54 Environment.GetEnvironmentVariable(
55 "SystemRoot"
56 ) + "\\Fonts\\";
57 if (File.Exists(systemFonts + fileName))
58 return systemFonts + fileName;
59
60 string rdwgFonts =
61 "C:\\Program Files\\Autodesk RealDWG 2007\\Fonts\\";
62 if (File.Exists(rdwgFonts + fileName))
63 return rdwgFonts + fileName;
64
65 return "";
66 }
67
68 public override string FindFile(
69 string fileName,
70 Database database,
71 FindFileHint hint
72 )
73 {
74 // add extension if needed
75 if (!fileName.Contains("."))
76 {
77 string extension;
78 switch (hint)
79 {
80 case FindFileHint.CompiledShapeFile:
81 extension = ".shx";
82 break;
83 case FindFileHint.TrueTypeFontFile:
84 extension = ".ttf";
85 break;
86 case FindFileHint.PatternFile:
87 extension = ".pat";
88 break;
89 case FindFileHint.ArxApplication:
90 extension = ".dbx";
91 break;
92 case FindFileHint.FontMapFile:
93 extension = ".fmp";
94 break;
95 case FindFileHint.XRefDrawing:
96 extension = ".dwg";
97 break;
98 // Fall through. These could have
99 // various extensions
100 case FindFileHint.FontFile:
101 case FindFileHint.EmbeddedImageFile:
102 default:
103 extension = "";
104 break;
105 }
106
107 fileName += extension;
108 }
109
110 return SearchPath(fileName);
111 }
112 }
113 #endregion
114
115 static void Main(string[] args)
116 {
117 // RealDWG specific
118 RuntimeSystem.Initialize(new MyHost(), 1033);
119
120 // Have the user choose the block and attribute
121 // names, and the new attribute value
122
123 System.Console.Write(
124 "\nEnter folder containing DWGs to process: "
125 );
126 string pathName =
127 System.Console.ReadLine().ToUpper();
128
129 System.Console.Write(
130 "\nEnter name of block to search for: "
131 );
132 string blockName =
133 System.Console.ReadLine().ToUpper();
134
135 System.Console.Write(
136 "\nEnter tag of attribute to update: "
137 );
138 string attbName =
139 System.Console.ReadLine().ToUpper();
140
141 System.Console.Write(
142 "\nEnter new value for attribute: "
143 );
144 string attbValue =
145 System.Console.ReadLine().ToUpper();
146
147 string[] fileNames =
148 Directory.GetFiles(pathName,"*.dwg");
149
150 // We'll use some counters to keep track
151 // of how the processing is going
152
153 int processed = 0, saved = 0, problem = 0;
154
155 foreach (string fileName in fileNames)
156 {
157 if (fileName.EndsWith(
158 ".dwg",
159 StringComparison.CurrentCultureIgnoreCase
160 )
161 )
162 {
163 string outputName =
164 fileName.Substring(
165 0,
166 fileName.Length - 4) +
167 "_updated.dwg";
168
169 Database db = new Database(false, true);
170 using (db)
171 {
172 try
173 {
174 System.Console.WriteLine(
175 "\n\nProcessing file: " + fileName
176 );
177
178 db.ReadDwgFile(
179 fileName,
180 FileShare.ReadWrite,
181 false,
182 ""
183 );
184
185 MyHost.WorkingDatabase = db;
186
187 int attributesChanged =
188 UpdateAttributesInDatabase(
189 db,
190 blockName,
191 attbName,
192 attbValue
193 );
194
195 // Display the results
196
197 System.Console.WriteLine(
198 "\nUpdated {0} instance{1} of " +
199 "attribute {2}.",
200 attributesChanged,
201 attributesChanged == 1 ? "" : "s",
202 attbName
203 );
204
205 // Only save if we changed something
206 if (attributesChanged > 0)
207 {
208 System.Console.WriteLine(
209 "\nSaving to file: {0}", outputName
210 );
211
212 db.SaveAs(
213 outputName,
214 DwgVersion.Current
215 );
216
217 saved++;
218 }
219 processed++;
220 }
221 catch (System.Exception ex)
222 {
223 System.Console.WriteLine(
224 "\nProblem processing file: {0} - \"{1}\"",
225 fileName,
226 ex.Message
227 );
228 problem++;
229 }
230 }
231 }
232 }
233 System.Console.WriteLine(
234 "\n\nSuccessfully processed {0} files, of which {1} had " +
235 "attributes to update and an additional {2} had errors " +
236 "during reading/processing." +
237 "\n[Press ENTER to close window]",
238 processed,
239 saved,
240 problem
241 );
242
243 // Delay the closing of the command prompt
244 System.Console.Read();
245 }
246
247 private static int UpdateAttributesInDatabase(
248 Database db,
249 string blockName,
250 string attbName,
251 string attbValue
252 )
253 {
254 // Get the IDs of the spaces we want to process
255 // and simply call a function to process each
256
257 ObjectId msId, psId;
258
259 Transaction tr =
260 db.TransactionManager.StartTransaction();
261 using (tr)
262 {
263 BlockTable bt =
264 (BlockTable)tr.GetObject(
265 db.BlockTableId,
266 OpenMode.ForRead
267 );
268 msId =
269 bt[BlockTableRecord.ModelSpace];
270 psId =
271 bt[BlockTableRecord.PaperSpace];
272
273 // Not needed, but quicker than aborting
274 tr.Commit();
275 }
276 int msCount =
277 UpdateAttributesInBlock(
278 db,
279 msId,
280 blockName,
281 attbName,
282 attbValue
283 );
284 int psCount =
285 UpdateAttributesInBlock(
286 db,
287 psId,
288 blockName,
289 attbName,
290 attbValue
291 );
292 return msCount + psCount;
293 }
294
295 private static int UpdateAttributesInBlock(
296 Database db,
297 ObjectId btrId,
298 string blockName,
299 string attbName,
300 string attbValue
301 )
302 {
303 // Will return the number of attributes modified
304
305 int changedCount = 0;
306
307 Transaction tr =
308 db.TransactionManager.StartTransaction();
309 using (tr)
310 {
311 BlockTableRecord btr =
312 (BlockTableRecord)tr.GetObject(
313 btrId,
314 OpenMode.ForRead
315 );
316
317 // Test each entity in the container...
318
319 foreach (ObjectId entId in btr)
320 {
321 Entity ent =
322 tr.GetObject(entId, OpenMode.ForRead)
323 as Entity;
324
325 if (ent != null)
326 {
327 BlockReference br = ent as BlockReference;
328 if (br != null)
329 {
330 BlockTableRecord bd =
331 (BlockTableRecord)tr.GetObject(
332 br.BlockTableRecord,
333 OpenMode.ForRead
334 );
335
336 // ... to see whether it's a block with
337 // the name we're after
338
339 if (bd.Name.ToUpper() == blockName)
340 {
341 // Check each of the attributes...
342
343 foreach (
344 ObjectId arId in br.AttributeCollection
345 )
346 {
347 DBObject obj =
348 tr.GetObject(
349 arId,
350 OpenMode.ForRead
351 );
352
353 AttributeReference ar =
354 obj as AttributeReference;
355 if (ar != null)
356 {
357 // ... to see whether it has
358 // the tag we're after
359
360 if (ar.Tag.ToUpper() == attbName)
361 {
362