Cadalyst Labs Review: Autodesk Inventor 11

Parts come together to build a 3D flagship

Compared with its 3D modeling competition, Autodesk Inventor got a late start out of the gate and has played catch-up since its first release. This time around, however, Inventor 11 has caught up with the competition in many respects, and in a couple of instances has surpassed it. Inventor 11 incorporates both the work of Autodesk developers and the fruits reaped from some of its acquisitions. This new version probably reflects the increased capabilities and options users can expect in the future, at least as far as the acquired technologies go. Inventor 11 is a result of all of the parts coming together, and it works in a cohesive and comprehensive manner.

Inventor 11 is an integral part of AIS (Autodesk Inventor Series), which also includes Mechanical Desktop 2007 and AutoCAD Mechanical 2007 for 2D work and Autodesk Vault for managing and synchronizing the mountains of data associated with most design projects. Inventor is also part of a package called AIP (Autodesk Inventor Professional) that includes everything found in AIS, plus additional specialized functionality for electromechanical routing (wire, cable, tube and pipe), stress analysis and importing printed circuit board IDF files for placement and packaging. In other words, you can't purchase Inventor by itself. You have to buy one of the two aforementioned packages. For this review, I'll focus exclusively on Autodesk Inventor 11 as found in both AIS and AIP.

Inventor installation and authorization is pretty painless and straightforward. Once started up and ready to go, Inventor 11 proved to be quite stable and not prone to crashes—always a good thing.

AUTODESK INVENTOR 11

Interoperability Improvements

If you import much data, such as IGES and STEP files, from different sources, you'll want to get acquainted with the improved tools in Inventor 11's Construction Environment for managing, modifying, inspecting and repairing imported data (figure 1). After all, what good is imported data if you can't actually do something with it? The Construction Environment really works this time around. It simplifies analysis and repair of imported data with workflows that use surface and wire geometry. When IGES or STEP data is imported, a separate Construction Environment browser is displayed in the model browser. Surface repair tools let you repair defective imported surfaces by using adjacent surface edges. With the new Promote Wires command, you can import wire data and transfer it to part or assembly environments, and it also can be used as lightweight reference data. I consider the data import and Construction Environment to be some of the most significant improvements to Inventor 11. The improvements were much needed, and although not perfect, indicate that Autodesk responded to user requests.

Figure 1. The Inventor Construction Environment provides fault-tolerant import of large STEP and IGES data sets and enables sharing and reusing of design data. It includes a comprehensive toolkit for inspecting, editing and correcting quarantined entities, including solids, surfaces, wire-frames and points.

In the Construction Environment, an interactive quality-check tool analyzes surfaces and reports conditions that could prevent you from using the data in Inventor. You can analyze several different types of errors, including geometry, topology, stitching and ambiguous. If Inventor's quality-check tool detects error conditions, it lists them and suggests a repair method. It also provides a link to additional information about the error condition.

You can demote Inventor or imported geometry to the Construction Environment and use tools to check quality, extend surfaces and trim or break surfaces. You then can promote the data back to the part environment. This capability can prove pretty handy. Finally, if imported data changes, you can associatively update changes between the old and new data.

Figure 2. Mastenbroek, the world's leading designer and manufacturer of made-to-measure trenching machines, designs new-generation hard-rock trenchers using Autodesk Inventor. This rendering demonstrates Inventor's ability to handle very large assemblies.

Managing Large Assemblies

Assemblies received a lot of attention in Inventor 11 with regard to configurations and management.

Assembly configurations are an efficient way to design and document product families. The basis for assembly configurations is something new known as iAssemblies. These are analogous in concept to iParts, which have been around for a while in Inventor. An iAssembly is a table-driven representation for a set of related assemblies. As with iParts, every row in an iAssembly table has a unique name to minimize confusion regarding what is what. When you create an iAssembly, you're then able to define related assemblies by editing the relevant iAssembly table. Each of these newly defined assembly members is a native Inventor assembly. You can make assembly-level modifications such as replacing and excluding individual component parts, adjusting constraint and parameter values and changing BOM (bill of materials) properties.

Speaking of the Inventor BOM, it supports iAssemblies and displays a single structure view that contains the aggregated item list. Each assembly configuration is displayed as a separate column showing quantity differences across different assembly members. With the BOM editor, you can display one member at a time or all members at once. Vault now also supports assembly configurations and lets you select and check in specific configuration members.

Figure 3. New to Inventor 11, AutoLimits help reduce errors—and engineering changes—by monitoring key design parameters and providing color-coded warnings when a parameter exceeds the design limit. AutoLimits can be used to monitor length, distance, angle, diameter, loop length, area, volume and mass.

One of the biggest requests all CAD software companies get is the ability to handle larger and larger assemblies, and Autodesk has addressed this issue quite well with Inventor 11 (figure 2). For example, large assembly management tools let you unload a subset of assembly components from memory while you work on the remaining components. A new capacity meter displays in the status bar to indicate the number of occurrences in the active document, the number of files opened and the amount of memory used.

Also, after suppressing components, you can create LOD (level of detail) representations that can be saved and reused for different types of design activities. During File Open, Component Placement and creating views operations, you can select the different LOD representation types. This enables very large assemblies to open more quickly by opening just the components necessary for the job at hand.

Figure 4. The Frame Generator in Inventor 11 streamlines the design of welded structural frames. Design and development of structural frames is fast with tools that automate the placement of predefined structural shapes and simplify creation of end conditions and welded joint cleanup.

Describing Complex Shapes

Like most of its competitors, Autodesk realizes the increasing importance of the ability to create cast and molded parts that require aesthetics, ergonomics and manufacturing constraints. Inventor 11 provides this capability with what's called shape modeling for better controlling sweeps and lofted features, as well as edge continuity and tangency. With shape modeling, Inventor 11 is becoming better suited for advanced shape description.

The new Sculpt tool is an easy way to create solids by combining surfaces and faces. Unlike Inventor's existing Stitch tool, the Sculpt tool does not require surfaces to be trimmed to common edges, and this difference really speeds things up.

Figure 5. Driven by the concept of Functional Design, Inventor lets you create designs based on the functional requirements of a product before committing to complex model geometry. In other words, you can put function before form.

As Inventor improves its ability to handle more complex organic surfaces, which are vital to the practice of industrial design, it will be interesting to see how it interfaces with the high-end surfacing capabilities found in the former Alias Studio Tools line that Autodesk acquired last year and now calls AliasStudio.

Other Major Features

I want to touch on a couple of capabilities that I consider significant in Inventor 11—AutoLimits and the Frame Generator.

AutoLimits are sensors or visual cues for monitoring critical design parameters such as length, angle, diameter and so forth (figure 3). Sensors can be created at the sketch, feature or document levels to visually indicate param-eters and their user-predefined allowable limits. After they are created, AutoLimits sensors track selected parameters and report any changes that drive a parameter outside its predefined limits through a series of color-coded icons. This tool is interesting and seems to work pretty well under the conditions and geometry I tried.

The Frame Generator is a tool and method that simplifies the design of structural machine frames and simple architectural frames. Frame Generator lets you select, place, trim and specify end conditions (miter, notch and so forth) for structural frame members (figure 4). For locating structural members, you can use 3D wire frames, edges and vertices of existing models. Frame Generator also is integrated with Inventor's BOM, as it should be. I'd like to see Frame Generator more tightly integrated with Inventor's Weldment environment, but that's something that might happen in a subsequent release.

Functional Design

Something that has really materialized this time around in Inventor is not a command or toolset, but rather a method or philosophy—something that Autodesk calls Functional Design. Functional Design is an evolving set of capabilities that reflect a different approach to 3D design. With Functional Design, form doesn't necessarily just follow function—instead, function can drive form. Although still relatively young with a lot of room to mature, Functional Design is a knowledge-content toolset that represents a movement from geometric descriptions to rudimentary knowledge capture. Functional Design isn't just a set of functions for creating 3D representations; it supports design by function (figure 5). There is much more to Functional Design than I can cover here, but it's an important aspect of Inventor that really sets it apart and will continue to do so as the product matures.

All in all, Autodesk's Inventor 11 is a major release that offers many new features and capabilities, added through direct development or acquisition. Inventor 11 has grown up and is ready to meet the competition head on, because although it's not perfect, it has come a long way.

Jeffrey Rowe is an independent design and technical communications consultant with offices in Colorado and Michigan. He can be reached at 719.539.8549 or jrowe@cairowest.com.