Through the Interface

Unlocking layers for certain AutoCAD commands using .NET

This question came up during last week’s accelerator, and is part of the reason I spent creating the last post: is it possible to selectively unlock certain layers for the duration of commands that have been specified by the user? Let’s take an example: you have layers that should remain locked, apart from when using the MOVE command (COPY and ERASE should not work). The approach I took was to maintain a dictionary mapping command names to lists of layers to unlock. When a command is launched – which we can tell using the Document.CommandWillStart event – we check... Read more →

Applying an operation to all the entities in an AutoCAD drawing using .NET

In the last post we saw a “general” function to erase all the entities in a drawing that fulfill a specified condition. We used it to erase all the zero-length lines in a drawing. But as I’d mentioned at the end, I thought there was an opportunity to generalize the mechanism even further. Here’s what I came up with (and I’ve included a suggestion by Parrish Husband to create an additional extension method for Curve.IsZeroLength()). using Autodesk.AutoCAD.ApplicationServices; using Autodesk.AutoCAD.DatabaseServices; using Autodesk.AutoCAD.Geometry; using Autodesk.AutoCAD.Runtime; using System; namespace ZeroLengthEntities { public static class Extensions { ///

/// Performs an operation... Read more →

Detecting and erasing zero-length lines in an AutoCAD drawing using .NET

A question came in by email, yesterday, and despite having a few mini-projects in progress that were spawned during last week’s event in Prague, I couldn’t resist putting some code together to address it. The developer wanted to purge zero-length geometry: the simplest way to solve the problem is to run “_-PURGE _Z” at the command-line, but I saw this more as an opportunity to create a simple helper that would loop through all the entities in a drawing and erase any meeting a specified condition. In this case it would be curves with a length less than the... Read more →

Launching AutoCAD’s REFEDIT command with an entity selected using .NET

A really interesting problem came up during an internal discussion, this week: someone wanted to launch the REFEDIT command on a selected xref and pre-select the entity found at the picked point. The entity that’s part of the selected xref, of course. This turned out to be quite a tricky problem and yet one that could be solved with relatively few lines of code. The tricky parts were finding the right entity in the nested selection and then the corresponding entity in the xref. Here’s the approach I ended up taking: Ask the user to selected a nested entity... Read more →

Fitting AutoCAD text into a selected space using .NET

After the last post, where we saw how to get the centroid of a Region, today we’re going to use that information to place some text inside a detected space. To restate our process from last time: The user selects a point Call Editor.TraceBoundary() to determine the containing space Call Region.CreateFromCurves() with the resulting geometry Determine the centroid of the Region Check whether the centroid is actually inside the Region If it is, then generate some text to place (we could also have asked the user for this, of course)… … and then calculate the size of the text... Read more →

Preventing AutoCAD objects from being purged using .NET – Part 2

In the last post we introduced a static C# class containing extension methods for the ObjectId and Transaction classes. The new Transaction methods allow you to more easily “lock” objects, whether because they’re “system” objects you want to keep around in every drawing or because they’re objects that shouldn’t be purged at whim by users. Under the hood, the implementation uses Xrecords stored in the Named Objects Dictionary that contain hard-pointer references to the various locked objects. This stops the PURGE command from removing them, but also allows us to check via Database.Purge() – or our new ObjectId.IsErasable() shortcut... Read more →

Preventing AutoCAD objects from being purged using .NET – Part 1

This is one of those topics that has been at the back of my mind for a number of years. Here’s a question I received via a blog comment back in 2009: I was wondering if there's an easy way to modify the objects to purge. For example, if a particular text style was included in the drawing that I did not want to be purged. Can this easily be done? Here’s how I responded, at the time: There are a couple of ways: You can maintain your own list of objects "to keep" and remove any items that... Read more →

Passing AutoCAD objects to commands called via .NET

This question came in as a blog comment on this previous post: Is possible to use Revision Cloud in this situation? Example: Creating a polyline/circle/ellipse then make it a revision cloud. It seemed to make sense to broaden the topic for the purposes of this blog post: how to pass an entity or entities to an AutoCAD command called via Editor.Command() or CommandAsync(). Since Editor.Command() was implemented in AutoCAD 2015, I’ve been a fan of the calling commands in AutoCAD application code. But I haven’t actually covered the approach needed to send object information to commands via this function.... Read more →

Checking for built-in AutoCAD objects using .NET

This interesting question came in by email from Igor, over the weekend: Let say I want to delete a layer by it's name. I can get ObjectId or LayerTabelRecord from the name, like LayerTable tLayers = (LayerTable) Transaction.GetObject(Database.LayerTableId,OpenMode.ForRead,false) LayerTableRecord ltRecord = (LayerTableRecord) Transaction.GetObject(tLayers.Item[Name],OpenMode.ForWrite,false); Now having LayerTableRecord how can I found out that this DBObject is not the built-in one? Like names '0' or 'DEFPOINTS'. Same goes for TextStyle (STANDARD) or layout (MODEL)….? I can't found any property regarding this, like IsBuiltIn. The IsPersistent property is no help. It’s true that there isn’t an IsBuiltIn property on AutoCAD objects… for... Read more →

Getting the extents of an AutoCAD group using .NET

Here’s an interesting question that came in from Nick Gilbert via a blog comment: Is there a simple way to get the geometric extents of the group? As discussed in this previous post, the Group object in AutoCAD presents itself as a collection of geometric objects (or entities, in ObjectARX-parlance). But a Group, in itself, isn’t a geometric object: it’s an aggregator of objects that are. So there isn’t – as Nick is clearly aware – a simple GeometricExtents property of the Group object. But we can access the contents of the Group and combine their various GeometricExtents, returning... Read more →

Preventing an AutoCAD block from being exploded using .NET (redux)

When I was a boy, I used to love going to play with toys at my grandmother’s house. My absolute favourite was a die-cast Batmobile made by Corgi in the UK. What I particularly liked about this toy was its hidden features: the cars apparently came with secret instructions, although these were nowhere to be seen by the time I started playing with it. The Batmobile had plastic flames that came out of the exhaust when the rear wheels turned and spring-loadable, vertical rocket launchers. The biggest surprise was when I discovered the cutting blade that popped out of... Read more →

Running custom .NET code in the cloud using AutoCAD I/O – Part 3

After introducing the series and looking at the additional code needed for a .NET CRX app to work with AutoCAD I/O, in this post we’re going to go the extra small step to prepare the Autoloader manifest, getting it ready to create the Activity and its AppPackage. To simplify the process of developing this app, I recommend a couple of things: download the sample on GitHub I pointed you at, last time – whether by cloning the project or downloading it as a ZIP – and make modifications directly to that. To build the sample I’m creating, for instance,... Read more →

Signing your application modules for AutoCAD 2016 – Part 2

Yesterday we introduced the need to sign program modules for AutoCAD 2016. Today we’re going to see how AutoCAD behaves when loading signed and unsigned modules, as well as what the innards of a signed LISP module look like. Here’s a simple piece of AutoLISP code that I’ve placed in a file called c:/temp/MyModule.lsp: (defun c:test() (princ "\nThis is a test command.") (princ) ) Here’s what AutoCAD displays when we try to load this module: We can use AcSignApply.exe to sign this module with our digital certificate, as we discussed yesterday: Here are the contents of the file once... Read more →

Signing your application modules for AutoCAD 2016 – Part 1

This series of posts is one I’ve been meaning to write since AutoCAD 2016 started shipping. Thankfully a number of other people have filled the void, in the meantime, so I’ve created an appendix of related posts that you can find at the bottom of each post in this series. The series is about how we’re working to improve security inside AutoCAD, and what this means for application developers. Dieter’s posts on Lynn’s blog help explain some of the background to this work, much as I’ve posted here in the past, too. Perhaps the biggest security change in AutoCAD... Read more →

AutoCAD 2016: Calling commands from AutoCAD events using .NET

It’s time to start looking in more detail at some of the new API capabilities in AutoCAD 2016. To give you a sense of what to expect in terms of a timeline, this week we’ll look at a couple of uses for DocumentCollection.ExecuteInCommandContextAsync() and next week we’ll look at point cloud floorplan extraction and (hopefully) security and signing. The first use of ExecuteInCommandContextAsync() I wanted to highlight was one raised in a blog comment a couple of months ago. The idea is simple enough: we want to be able to launch a command reliably from an event handler, in... Read more →

AutoCAD 2016 for developers

After our quick look at AutoCAD 2016 from a user perspective, let’s now spend some time looking at the things important to developers in this latest release. Compatibility Off the bat it’s worth stating that AutoCAD 2016 is a DWG compatible release: it’s using the same file format as AutoCAD 2013, 2014 and 2015. It’s also a binary application compatible release: ObjectARX apps written for AutoCAD 2015 should work in 2016 and it’s likely that .NET apps built for AutoCAD 2014 will work, too. That said, some changes have been made to the security model for this release of... Read more →

Docking a WPF window inside AutoCAD – Part 3

In this post we’re wrapping up this mini-series on docking, which is part of a much broader story arc around a “command-line helper” tool, of course. But then we’re reaching the end of that, too, I suspect, as the app’s just about done. Hopefully it’s ready for posting to Autodesk Labs, at least. Last time we added right-click dragging to allow our keywords window to be moved around without interrupting the active command. Now we’re taking it a step further to preview docking at one of the four corners of the drawing window, as well as to actually dock... Read more →

Docking a WPF window inside AutoCAD – Part 2

I’m happy to say that the implementation I mentioned in the last post ended up being pretty straightforward. Which is actually great, as I have some important posts to work on for next week. :-) Today we’re going to take a look at the next stage of the “command-line helper” implementation: basic right-click movement of the global keywords dialog, so we can set a custom location for the dialog without needing to use the KWSDOCK command. Here’s the code in action: The main work for this stage was to add support for right-click, mouse move and right mouse-button up... Read more →

Adding support for global keywords at AutoCAD’s command-line using .NET – Part 2

Today we’re going to look at the implementation talked about in the last post: we’re going to see how it’s possible to use the Application.PreTranslateMessage() method to hack AutoCAD’s message-loop and basically convert typed keywords into global ones. This is actually pretty neat (yes, even if I do say so myself :-) and frankly I’m surprised it works. Here’s the overall approach: Track the characters typed into the command-line Add individual characters into a list Backspace removes the tail of the list Arrow-keys invalidate the tracking: if the user accesses entries in the command-history we can’t deal with that,... Read more →

Adding support for global keywords at AutoCAD’s command-line using .NET – Part 1

This post carries on from this series from a couple of weeks ago: Adding a global keyword menu to AutoCAD using WPF – Part 1 Adding a global keyword menu to AutoCAD using WPF – Part 2 Enabling global commands on localized AutoCAD versions using .NET The overall goal behind these posts was to create a “command-line helper” tool to make it easier for people who know the English version of AutoCAD (or an AutoCAD-based vertical) to work with a corresponding localized version. Basically because some people learn AutoCAD using an English version – perhaps during their studies –... Read more →