AutoCAD Mechanical 2006Proof That 2D Mechanical Design Is Not Dead

3 Aug, 2005

It’s 2005 and by now practically everybody who designs mechanical things for a living has made the switch to 3D because 2D is dead, right? I would say not, for a couple of reasons. First, many users of 2D CAD products are comfortable staying with 2D, and 2D suits their needs. Second, some types of mechanical design, such as machines, just don’t necessarily need a 3D tool. So why switch? With the release of AutoCAD Mechanical 2006, Autodesk continues to give life to its 2D mechanical design and drafting package.

AutoCAD Mechanical is a specialized 2D application that sits on top of and is tightly integrated with AutoCAD. Look at the interface and you can tell immediately that they’re obviously related, but also different, because Mechanical has toolbars and palettes specifically for mechanical design, such as standard parts libraries, mechanical line objects and simple FEA (finite-element analysis) calculations for 2D objects. For a 2D mechanical design package that retails for just $450 more than plain AutoCAD ($4,195 vs. $3,750), it’s worth the extra money for an application that has been optimized for 2D mechanical design and drafting. You can also get AutoCAD Mechanical 2006 as part of the Autodesk Inventor Series 10 ($5,195) that also includes Mechanical Desktop 2006 and Inventor 10.

Mechanical Structure

Probably the single most significant feature in AutoCAD Mechanical 2006 actually began with the 2004 release, something called mechanical structure. It’s used for organizing geometry into components for easy reuse. It displays such components in a tree-like format in a graphical browser similar to those found in Mechanical Desktop, Inventor and other 3D modeling products. Initially, you may find the concept of mechanical structure somewhat complicated, but once you get the hang of it, I think you will see it as a powerful aspect of AutoCAD Mechanical. Mechanical structure lets you organize mechanical design and drawing data in a way that blocks, groups, and layers never could (but these can still be used in conjunction with mechanical structure).

Before using mechanical structure, first make sure that it’s turned on. You do this by opening the Options (AutoCAD’s Options and Mechanical’s Options are merged) dialog box from either the menu or command line, clicking the AM:Structure tab and checking the Enable Structure checkbox. Next, you’ll want to select the design mode, top-down or bottom-up, that best suits the way you work. Although either method gives you the same end result, the way you reach the result are exactly opposite. A top-down approach begins with a top-level component, usually a part or assembly, and ends with the elemental geometry as displayed in the browser. A bottom-up approach begins with elemental geometry and end with the top-level component. Most users will probably prefer the top-down approach, because they can select and work with an entire component rather than its elemental geometry.

You can also set filters to hide views and features in the browser, but all geometry can be selected and edited at any time. You can reorder components and organize them into different subassemblies and views, and the BOM (bill of materials) database ensures that each separate view isn't counted in the BOM. If you copy a structured element, the copy is created from the stored definition, and each component view instance can have independent view locations. The browser also keeps track of multiple instances of components, so a change to one is automatically reflected in all instances in an assembly.

The associativity of mechanical structure makes it much easier to annotate designs than in previous releases. Annotation views appear in the browser with a special icon and are designated with (AV) at the end of the component name.

If, for whatever reason, you don’t want to use mechanical structure (although I strongly recommend using it), uncheck the Enable Structure check box to disable it whenever it would automatically be created, such as during insertion of standard parts, calculations and hides.

Overall, mechanical structure is the major feature that sets AutoCAD Mechanical apart from regular AutoCAD for mechanical design. Although you’re in a 2D design environment with AutoCAD Mechanical, the mechanical browser and the way components, views, etc. are arranged are also subtle introductions to the way 3D (Inventor) works and may help ease the inevitable transition to 3D. How long before you’ll face this transition? Autodesk says it is committed to AutoCAD Mechanical development and support for the foreseeable future, and will ship it concurrently with future releases of AutoCAD and as part of the Autodesk Inventor Series.

So, is 2D for mechanical design dead? I hardly think so.

If you’ve been using either AutoCAD or AutoCAD Mechanical for your mechanical design work, and are happy with the inherent advantages and limitations of working in 2D, AutoCAD Mechanical 2004 is worth serious consideration as an upgrade or replacement.