Autodesk Inventor R4 (Taken from eWeekly Issue 74)
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Autodesk, on 21 Dec. began shipping Release 4 of Autodesk Inventor, only five months after Release 3 began shipping. Autodesk focused this release on providing better transitions for customers from 2D to 3D. The release includes over 150 enhancements along with DWG file compatibility. Inventor continues its emphasis on rapid learning (called single-day productivity), adaptive technology, and large-assembly modeling. See our assessment of their success in these areas in the review below.

In ease-of-learning improvements there are enhancements to sketching, such as automatic dimensioning and support for unconsumed sketches that allows them to be cataloged for future use; new iMates technology helps users define how parts will automatically snap into position in the assembly, and a new Sketch Doctor helps users with sketch and drawing recovery, especially when importing legacy data from other design programs.

Inventor users can import legacy drawings in DWG format to use as a starting point for a new model or as a reference "backdrop'' for a top-down modeling session. Users can also export DWG files to communicate with suppliers and customers who rely on the world's most widely used drawing format for design communication.

A new Dimension Style Manager provides more section lines capabilities, extensive bill of materials enhancements, and rotated auxiliary views. Inventor software also can create 2D parametric-driven production drawings.

Inventor's adaptive technology and large assembly performance have been further enhanced. Adaptive technology has been extended to accommodate multilevel adaptive solving, helpful for designers of complex mechanical systems. Family-of-Parts publishing controls the parameters that users can access in parts, promoting more part sharing. Assembly file sizes in Autodesk Inventor 4 are four to six times smaller, constituting a 60% to 80% decrease in file size from Autodesk Inventor 3.

Inventor 4 introduces surfaces for creating complex shapes and adds more depth and breadth to sheet metal design. Simultaneous folded and unfolded design methodology has been extended to include punched shapes across bends, flanges with setback, and ripped corners. The English language version of Autodesk Inventor 4 is currently available in the United States and Canada. International language versions will become available later. www.autodesk.com/inventor

Feedback on our review

Early last month we met with Jay Tedeschi, Senior Applications Engineer, MCAD division of Autodesk, to briefly review the highlights of Inventor R4. I say briefly because we only spent about 1.5 hours together. I particularly asked Jay to focus on where R4 differs from its competitors.

Since Jay was working on a very large model, I was immediately impressed by the adaptive degradation. This degrades the tessellated image on the display so that it can keep up the frame rate that we requested in terms of moving through large assemblies. Stopping any movement allows the image to complete itself in the background - just like streaming technology works. Very nice for large models.

One unique capability of Release 4 is tighter integration with drawings and data collected by AutoCAD in DWG format. In one example, we were automatically able to import a DWG drawing and convert it into Inventor format. Once imported into Inventor, the drawing converts itself from the DWG format into the native IDW (Inventor) file format. We used predefined dimension styles that were defined in AutoCAD and brought the entire file into Inventor using a template. In the case of importing DWG, the template is just used for sheet sizing. Similar to other systems, such as Solid Edge, the DWG line styles and other data types are converted using a translation table organized within Inventor. Inventor Release 4 does not support layers on import nor does it maintain them. On output, Inventor places objects on layers. These output layers depend upon the object type and are not controllable.

One interesting capability is that Inventor can now use the dimensions that were imported from DWG. The dimensions do not have to be recreated, they can be "promoted to the sketch" to become driving dimensions (parameters). We also had an opportunity to look at the new Sketch Design Doctor. It notified us that there were certain, in our case, dimensions that were unattached to geometry. We were able to associate dimensions that evidently were unassociated in AutoCAD, by selecting the dimension and reattaching it to a point in the imported drawing. Upon promoting the dimension to a sketch, we can then immediately have use of the parameters in that sketch which were the dimensions that were promoted.

We briefly looked at the ability for Inventor Release 4 to auto-dimension and auto-constrain the sketch. This is new in Release 4. We observed a interesting and apparently highly efficient user interface, strictly operated by the mouse, that enabled us to constrain certain geometry to others by merely dragging at the appropriate spot and relating it to other geometry in the sketch. Jay called this - visual constraint scheme feedback.

In a demonstration of some simple techniques, we developed and completed the pillow block. (See the related images). To do this, we started with a DWG profile. The other thing we picked off was a visual observation of the dimension so we can build a 3D model to the right size.

A new function (called iMates) allows the user to define a series of named assembly constraints. When you place a part into an assembly, Inventor will look for constraints on the other part that have the same names and automatically match up the mating conditions. In the pillow block example, we saw it was set up with the three required mating constraints which, were face to face and two concentric centerline conditions. Unfortunately, this did not work -- because of the beta version of the software we were using? I assume this will work in the delivered version.

About adaptivity

The other things we looked at were an attempt to have Jay explain to me what adaptivity was. We took a look at adaptive subassemblies and adaptive layout. The adaptive subassemblies were quire interesting. Jay claims that AutoDesk Inventor 4 is the only Mid Range CAD system able to actually propagate mechanism functionality between assembly subsystems, to any sub assembly depth, because of the adaptivity of the system.

We looked at two other items. One was adaptive layout. This was interesting and has been in the system since Release 1. We placed a 2D-connector rod into a 3D solid assembly. The connector rod was directly read from an AutoCAD 2D DWG file. Then we were able to place this into our 3D subassembly. The part that we imported happened to be correctly sized to meet the two mating lever arm points. If this was not the case, we could have changed the lever arm to become adaptive so that its size would change.

Making a mass change so that an entire drawing or part becomes adaptive is probably not a good procedure. You want to allow certain dimensions or parameters of the part to allow them to become adaptive. The way to make this happen is to un-dimension certain portions of the part so that that they are allowed to modify adaptively. Alternatively, you might allow a part to be fully adaptive (thus having no idea as to what parameters would change and how), make the change and if it does not meet expectations, restrict some of the parameters from being adaptable.

In essence, this is a variation of what SDRC a few years ago called "variational design." Instead of just forward solving for parameters, the system uses a set of simultaneous equations to try and resolve the problem. The more free parameters there are, the easier to solve the problem. Unfortunately, freeing to many parameters often generates undesirable solutions. Write us if you are interested in more detailed discussions on this topic and we will try to get a thread going.

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In the referenced images we have also included an AVI file of a 2D parametric-driven production drawing of a "Suzuki full floater."

Another major portion of Release 4 enhancements are to sheet metal. The previous version had a barely workable sheetmetal system. R4 claims to have fixed this. Unfortunately we did not have a chance to review these enhancements. Perhaps in the near future. We also encourage anyone using the new sheetmetal functions to write us with their experiences.

Conclusions

Frankly I was impressed with the enhancements to R4. Certainly any user with large numbers of AutoCAD drawings will find R4 a much easier transition than its predecessor. This is a good first step to better compatibility with DWG. We look forward to more enhancements in this area soon to make it even better.

I also, once again, liked Inventor's ability to manipulate, using its streaming technology, very large assemblies with no special attention required by the user. This became obvious during the demo when we were dealing with more than 800 parts in the model.

In addition, Autodesk seems to be on a fast track with new releases, finally.

Evidently customers are beginning to agree also. A recent deal closed with Applied Materials for what was rumored to be more than 1000 seats of Inventor.