Through the Interface

Securing your AutoCAD app using .NET

Many, many thanks for the congratulatory messages I received after my last post, whether via this blog, Twitter, LinkedIn or email. I was genuinely overwhelmed by the response! :-) Here’s a post I’ve been meaning to write for some time: a common question I’ve seen, over the years, is about how best to implement copy protection or licensing in your application. While this post doesn’t fully address that requirement, it does show you how to use a REST API to check the user entitlement for your application via the Autodesk App Store (formerly known as Autodesk Exchange Apps). This... Read more →

Capturing an image of the current AutoCAD document using .NET

This is a topic that has been addressed a few times on this blog, whether by posts that use the 3D graphics system to capture screenshots or the series of posts regarding the Screenshot Plugin of the Month from a few years ago. I thought it worth revisiting, though, as I noticed an API that I hadn’t used before and decided to put it through its paces. The API is a simple one – Document.CapturePreviewImage() – and it’s been covered before on the AutoCAD DevBlog. But I thought I’d take some file-selection code from the Screenshot app and see... Read more →

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 →

Locking and unlocking AutoCAD layers visibly using .NET

On Friday I visited Munich Airport: not only to catch a flight home to Switzerland but also to take a look at some AutoCAD issues frustrating the developers working on the airport’s facilities management system. During the course of the day we were able to work through a number of problems – such as using COM (SendCommand()) to run a script synchronously as well as to get the fill pattern for MPolygon objects (this is apparently broken in .NET) – but there was one I had to bring home with me: when locking and unlocking layers programmatically, their geometry... Read more →

Accelerating in Munich

It’s been a hectic – but very fun – few days in Munich, working with a group of 60-70 developers from all over Europe who are getting started with Autodesk’s cloud services. I’m particularly focused on those working with AutoCAD I/O, which means probably 5-6 companies in total. Here’s a quick summary of some of the problems that have come up, many of which are for pure AutoCAD… Draw Order warning One developer has a long-running custom operation that presents the following message: AutoCAD Warning: This operation may take a long time. To greatly improve performance, the system can... Read more →

Controlling robots from inside AutoCAD – Part 4

I wasn’t planning on writing another part in this series, just yet, but then I got a little carried away with some refactoring work and decided it deserved a post of its own. I wasn’t fully happy with the code in the last post. The DecomposeCurve() function simply did too much: it opened a curve, extracted the points we were interested in and then created “movement” strings for each segment connecting the points. So the function was just way too single-purpose, even if a number of the individual operations being performed could potentially have been of use elsewhere. So... Read more →

Controlling robots from inside AutoCAD – Part 3

After seeing how we can use Cylon.js to control Sphero’s Ollie and BB-8 robots from a browser, and then using the same mechanism from inside a custom AutoCAD command, today we’re going to drive these cute little bots based on AutoCAD geometry. The idea is that we’ll decompose regular curves – whether lines, arcs, polylines or splines – and use the “segments” as movement instructions for our robots. The approach is simple enough: we’ll iterate along the length of each selected curve and generate a set of instructions – really just a set of angles – for the associated... Read more →

Controlling robots from inside AutoCAD – Part 2

After looking at how to control robots using Cylon.js in the last post, in this post we’re going to get that working inside AutoCAD. For now with just a command that allows us to move the robots – in a future post we’ll analyse geometry and use that to specify the movements. The “controller” code we saw in the last post needed a little updating for use in this way. I went ahead and stripped out the keyboard-related code – as we’re using behind a web-service – and added the capability to control individual robots. We want to be... Read more →

Determining AutoCAD’s status bar coordinates using .NET

This came up during an internal discussion and I thought it worth sharing here. It’s easy enough to use a point monitor in AutoCAD to determine the current cursor location, but how do we make sure it’s in the current User Coordinate System (UCS) and that we adjust for object snapping (osnap)? To keep the code simple I’ve been a little lazy: I’m just adding an event handler as a lambda, without worrying about removing it. Also, to avoid a crash when you switch to the New Tab page or a new document and back, the code swallows an... Read more →

The Force Awakens in AutoCAD

Some of you may remember this series of posts from the beginning of the year (I also mentioned it in the last post). It showed how you might use AutoCAD and .NET (in this case via F#) to animate the Star Wars opening crawl for the first 6 movies. Back then I said I’d update the video series to include Star Wars Episode VII: The Force Awakens, once it was released. Today is that day… due to some bizarre accident of international scheduling, I got to see it two days ago, here in Switzerland. I took a few snaps... Read more →

Creating AutoCAD Xrefs as overlays with relative paths using .NET

After showing how to automatically attach xrefs at the origin inside AutoCAD, and then redoing the approach to take care of different unit systems, I then had the request from a couple of places to look at making the xrefs overlays and adjusting their paths to be relative rather than absolute. Looking around, I found some code on the AutoCAD DevBlog that changes an attachment to an overlay, after the fact. Henrik Ericson found the code didn’t work for him, but did spot the db.OverlayXref() method which did. So I went ahead and made use of that for overlays.... Read more →

Converting units between different AutoCAD drawings using .NET

This is actually a redo of last week’s post, just with a different title: while the approach shown worked well when creating external references to drawings using the same units, when bringing in (for instance) metric xrefs into an imperial master drawing the scale was all messed up. Thanks to Hans Lammerts for reporting the issue. The scaling ended up being straightforward to implement: the hard work was done by UnitsConverter.GetConversionFactor(), which established the scale factor to use, converting between the Units property of the new block table record and the Insunits property of the target database. Then it... Read more →

Creating an AutoCAD layout with custom plot and viewport settings using .NET

This request from Thomas Longnecker languished in my inbox for several weeks before I finally found the time to work on it. It would be tremendously helpful to me if you could give an explanatory example of how to: Create a new layout, add a page-setup with plot-settings and then either delete the default viewport and create a new one or possible change the default viewport. […] Within the newly created layouts I needed to set some of the general Plot setting, mainly Paper size and Plot style table. Some of the main things for the viewport was to... Read more →

Attaching AutoCAD Xrefs and inserting them at the origin using .NET

I just received this interesting (and quick to solve) question from Henrik Ericson, this morning: I’m looking for a new xref command (or perhaps overriding the internal xref command) that always insert the selected xref at 0,0,0 coordinates and in World coordinate system. I’m often inserting an xref and ’nothing happens’ and then I realize that I’m in a UCS. I created a simple command called XAO – for XrefAttach[At]Origin – that does just this. As a helper function I implemented a simple extension method to both attach and insert an external reference in the current space of the... Read more →

Mapping Zork inside AutoCAD – Part 2

In the last post we saw how we could integrate an HTML and JavaScript palette hosting Cytoscape.js into AutoCAD to map progress made in a text adventure. In today’s post we take the additional step of converting the graph data into AutoCAD geometry. To be clear, there’s a bit more to this post than having fun mapping old-school interactive fiction inside AutoCAD: I can think of lots of scenarios where you might want to use a comparable tool to build a graph of data and lay it out manually before bringing the graph into AutoCAD as native geometry. But... Read more →

Mapping Zork inside AutoCAD – Part 1

I mostly despise jetlag but once in a while manage to harness it for something positive. I remember some great trips to Asia, waking up at strange times to experience the dawn, walking the streets and seeing everyday life starting up around me. These days I typically find jetlag to be a bit of a curse, but this weekend I ended up using it to tackle a fun challenge: generating maps for Z-machine games such as Zork inside AutoCAD. Something I mentioned in a recent blog post but was reminded of last Thursday while catching up with Christer Janson... Read more →

AutoCAD I/O v2

The AutoCAD I/O team has deployed version 2 of their API. For specific information on what’s new, check this page. As I’ll be talking about AutoCAD I/O at AU 2015, I thought it important to get to grips with the new version and understand how it differs from v1. I went ahead and updated Jigsawify.com to make use of the new API, so I’ll add my own commentary below on the changes that have been introduced. As a reminder, the full source code for Jigsawify.com is available on GitHub. To check out the specific migration changes, see this comparison... Read more →

Displaying different entities in AutoCAD viewports using .NET

This is a problem that developers have been struggling with for some time, and it came up again at the recent Cloud Accelerator: how to control the display of AutoCAD geometry at a per-viewport level, perhaps to implement your own “isolate in a viewport” command. It’s certainly possible to control layer visibility at the viewport level, of course, but this is sometimes at odds with how users wish to use layers for their own purposes. An application may want to isolate geometry in a certain location from a number of layers, for instance, and it becomes cumbersome to hijack... 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 →