Autodesk Inventor 2008 (Cadalyst Labs Review)

New release is quick on the DWG.

When I first saw a prerelease version of Inventor 1, Autodesk emphasized that the product was Autodesk Inventor, not AutoCAD Inventor. In fact, a worthy competitor bragged that its parametric modeler was more compatible with AutoCAD than Inventor was. This matter of compatibility has changed with each successive release, as Inventor has become capable of importing AutoCAD geometry.

Inventor 2008 finally makes the great leap forward in AutoCAD compatibility. Some have said that it's now so AutoCAD-compatible that it's finally a full member of the family, and so Autodesk has switched to the year-based version numbering of other products (perhaps also because 12 was getting too close to unlucky 13).

By far, the biggest news in Inventor 2008 is its support for a new file format when creating 2D working drawings from a 3D part or assembly. It continues to support its native IDW format, but users can use its new DWG format as well.

Autodesk Inventor 2008

Hold on! Isn't DWG supposed to be AutoCAD's format?

Correct. Inventor 2008 will now let you create a 2D drawing file in DWG format. Better than that, it isn't just a one-time translation when you're finished. Inventor DWG files remain fully parametric and associative back to the Inventor solid model. If a user changes a model, the DWG file will update, and if he or she changes a dimension in the drawing that was retrieved from the model, the model changes.

Inventor DWG files can be opened in AutoCAD 2008 with an interesting twist. Each sheet of the Inventor DWG file becomes a flat, 2D layout in paper space in AutoCAD. There are no model-space or 3D objects in the file.

Users can edit files in AutoCAD with certain limitations. They can use all of the normal creating and editing functionalities in AutoCAD, except they can't edit the views of the actual part or assembly. They can delete or explode the dimensions and other annotations that come across from Inventor, and they can snap to objects within the part if they wish to apply new dimensions, but they can't move, copy, delete or explode the views of the part.

The obvious intent is that the Inventor DWG will be created and edited by the design department using Inventor 2008, but downstream users can't mess with the integrity of the basic views of the part.

3D, Here We Come!

A major stumbling block in getting users to move from 2D to 3D is abandoning all of their legacy AutoCAD files. Inventor 2008 now takes care of this predicament.

Assume you have an older 2D AutoCAD drawing of a large machine assembly and you want to redesign a portion of it. Previously, you would have needed to model the entire existing machine in 3D in Inventor just to create an Inventor 2D drawing that showed the current machine configuration. Obviously, most companies will stick with 2D applications under these conditions.

Inventor 2008 has the solution to this problem. All you need to do is model the new portion in Inventor then create a new Inventor 2D DWG from the model. The cunning part here is that each view in the Inventor DWG file is actually an AutoCAD block (figure 1). Simply open the existing file in AutoCAD, delete the obsolete portions and then use Design Center to insert the new views from the Inventor DWG file. That's it! You've now created a hybrid AutoCAD drawing. Everything in it is 2D, but when you update the Inventor 3D model, the Inventor DWG also updates. Now go back to AutoCAD, where the Design Center can be used to quickly update the block definitions in the legacy file. Bingo! No more 2D-to-3D transitioning hassles.

Figure 1. 2D-to-3D transition from top to bottom: A new Inventor part is used to create an Inventor DWG file. Then a view is extracted from it and inserted into an existing AutoCAD 2D drawing.

An Inventor DWG file will survive a round trip through AutoCAD and back without harm. It's still associative and parametric. A new object enabler under development will allow AutoCAD 2007 the same access to Inventor 2008 drawings.

How Much Longer Is It?

Inventor 2008 adds a number of annotation improvements. Figure 2 shows two of my personal favorites: axonometric hatching and dimensioning.

Figure 2. Inventor 2008 supports axonometric hatching and dimensioning.

It's possible to apply axonometric dimensions directly to pictorial views. They can be associative dimensions retrieved from a model, or they can be placed as drawing dimensions. The best part of this functionality is that it's not restricted to the standard isometric views; it can be applied to any axonometric viewing angle. Dimensions automatically show the true lengths rather than foreshortened values, as in the past.

Hatching has two major enhancements. The first is that hatching can be applied to axonometric sections, and the second is that hatch patterns can be associated with specific materials. The procedure goes something like this: Attach a pattern to a material, use iProperties to apply the material to a part and use the part in an assembly. Section views, including axonometric section views, of a single part or assembly will show the hatch pattern associated with the material for each part.

Another improvement to the creation of 2D drawing views is that users can turn the visibility of specific views on and off. For example, to create the sectioned isometric view in figure 2, I had to create a base top view, then a section view and finally the projected isometric view. In previous releases, the unwanted views would have to be dragged outside the drawing sheet area, a step that sometimes created its own problems. The new process is much better.

Inventor 2008 definitely seems to be the look-at version, but not all of the new or improved visual functionality is limited to 2D drawing views or AutoCAD files. The first obvious difference is the new tool tip cursor. When Inventor was introduced, Autodesk touted that it didn't have a Command line. That's fine as far as it goes, but users still need to be prompted for the type of input that is expected. Until now, this prompt was handled by a small, barely visible window in the lower left corner of the screen. With Inventor 2008, user prompts are handled by a discreet tool tip cursor (figure 3). It's big enough to be seen but not so busy as to be overwhelming.

Figure 3. The new tool tip prompt is informative but not overwhelming.

Other look-at improvements include the rationalization of icons between AutoCAD and Inventor and better consistency with Windows file dialog boxes. Autodesk also made several improvements to the Show Constraints tool.

Lest one get the impression that all of Inventor 2008's improvements lie in the AutoCAD and look-at area, rest assured that several hundred additions and enhancements were made in virtually every area.

Software companies use internal names during the development phase of a new release. Inventor 2008 was called Goddard, implying perhaps that Autodesk hopes for it to take off like a rocket. Highly Recommended.

Bill Fane is a Cadalyst contributing editor and a professor at the British Columbia Institute of Technology. E-mail him at bill.fane@cadalyst.com.