Through the Interface

Making AutoCAD objects annotative using .NET

In the last post we looked at how to add a new annotative scale to an AutoCAD drawing. In this post we'll look at what's needed to make an object annotative - providing it's of a type that supports annotation scaling, of course. Once again, this post is based on functionality introduced in AutoCAD 2008. I hit my head against the problem for a while, having tried my best to convert the technique shown in the AnnotationScaling ObjectARX sample (which uses a protocol extension to access objects stored in an annotative entity's extension dictionary) to .NET. I finally ended... Read more →

Adding a new annotation scale in AutoCAD using .NET

Thanks to Nikolay Poleshchuk and Roland Feletic for suggesting this topic, and to Wayne Brill, from DevTech Americas, for providing the code. In this post we're going to look at some functionality that's specific to AutoCAD 2008 - adding a new annotative scale to a drawing. The next post (assuming I can work out how to do it :-) will cover how you can attach a scale programmatically to make an entity annotative. Firstly, I should cover what the annotation scaling feature is all about... Here's a quick overview from the AutoCAD 2008 online help: Objects that are commonly... Read more →

Loading the right version of an ObjectARX module into 32- or 64-bit AutoCAD

This question has come in from a number of developers... How can I tell when my application is running inside a 64-bit version of AutoCAD? As mentioned in this previous post, AutoCAD 2008 installs as native 64-bit binaries on a supported 64-bit OS, just as 32-bit binaries get installed on a supported 32-bit OS. A minor complication is that certain of our AutoCAD-based products do not yet have native 64-bit versions. Our Engineering teams are working on this, but in the meantime, your application might well be working inside a 32-bit Autodesk product on a 64-bit OS. So how... Read more →

Taking a snapshot of the AutoCAD model (take 2)

In this previous post, we looked at some code to do a programmatic snapshot of AutoCAD's modelspace, saving the results to an image file. From the discussion that followed, I realised that the code had an undesired (and unnecessary) side-effect of creating a new 3D GS View and leaving the modelspace with that view active. GS Views in AutoCAD 2007 have grey backgrounds by default, and so this change can be quite disturbing for users. The only reason we created the GS View in the first place (if one didn't already exist), was to use it to query the... Read more →

Autodesk University customization sessions

My team is currently working on a proposal to deliver a significant number of additional API- & customization-related classes at this year’s Autodesk University. We’re planning to hold sessions covering many of our products’ APIs, including (hopefully): Platform products & technologies AutoCAD Component Technologies (RealDWG, AutoCAD OEM, DWG TrueView, DWF Toolkit, Design Review, Freewheel) AEC Revit Architecture Revit Structure Revit MEP AutoCAD Architecture AutoCAD MEP AutoCAD Civil 3D Manufacturing Inventor AutoCAD Mechanical AutoCAD Electrical Productstream Geospatial AutoCAD Map 3D Topobase MapGuide Enterprise Media & Entertainment Maya 3ds Max MotionBuilder Here are the some of the sessions we’re thinking about... Read more →

New Autodesk Labs blog

Scott Sheppard - the original author of the very informative DWF blog, Beyond the Paper - has launched a new blog talking about Autodesk Labs, called It's Alive in the Lab. I'm looking forward to seeing lots of cool information on Labs technology coming through this blog. Read more →

Iterating through a polyline's vertices using AutoCAD .NET

I was inspired by some code sent out by Viru Aithal to write a command that iterates through the vertices of the various types of AutoCAD polyline: Optimized (or "lightweight") 2D polylines, which store an array of 2D vertices Old-format (or "heavyweight") 2D polylines, which contain a sequence of 2D vertex objects 3D polylines, which contain a sequence of 3D vertex objects Polylines that contain vertex objects are containers for the object IDs for the various vertices - you can use foreach to loop through the vertex objects, opening them one-by-one. For optimized polylines we need to loop using... Read more →

Taking a snapshot of the AutoCAD model using .NET

This topic is a follow-up to the previous post dealing with offscreen rendering, and was suggested (and is based on code provided) by Fenton Webb, a member of DevTech Americas who has just moved across to San Rafael. Fenton was until recently part of DevTech EMEA, working from the UK. The basic technique is similar to the one used in the previous post: we use the graphics system to create an "offscreen device", which we then set up and request to create a snapshot of our model. This can work on graphical objects stored in any AutoCAD database, but... Read more →

Rendering AutoCAD models offscreen using .NET

This question came up in an internal discussion, and I thought I'd share the code provided by our Engineering team with you (with a few minor additions from my side, of course). The idea is to render a 3D scene off-screen (i.e. save to file the rendered image not visible in the editor). In the below code, we do zoom to the extents of the 3D model that gets created, just to show it's there, but the rendering activity itself is not performed by the 3D view that is used to generate the graphics for AutoCAD's editor window. A... Read more →

Adding XData to AutoCAD entities using .NET

A follow-up question came in related to the last post, around how to add XData to entities using .NET. Extended Entity Data (XData) is a legacy mechanism to attach additional information to AutoCAD entities. I say "legacy" as there are limits inherent to using XData, which make other mechanisms more appropriate when storing significant amounts of data. The global XData limit is 16 KBytes per object, and this potentially needs to be shared between multiple applications. With AutoCAD 2007 came the complete switch to Unicode for string representation, which increases the storage requirements for strings in XData. Internally, the... Read more →