Over the years a number of software products that began and succeeded in one market attempted to cross over to other market segments with widely varying results. Some did quite well, some did OK, and some failed miserably. The difficulty lies in the different demands and expectations inherent in different market segments, not to mention different requirements and workflows. Adobe Acrobat 3D Version 8 is one of the more recent and prominent software packages trying to translate the success it has enjoyed in the publishing world to mechanical engineering/design/manufacturing and associated CAD. Let’s take a brief look at how Adobe has fared so far with Acrobat 3D V8, but first a little background.
Although it’s called version 8, this new version is actually only the second one focused on CAD data, but offers a very comprehensive suite of tools and utilities for converting 2D and 3D models to the universally-used PDF format.
The first version of Acrobat 3D was based on Intel’s U3D open format for handling 3D data, but it quickly proved to not be the most efficient or accurate way to go, because it was a tessellated approximation of a model that had to be captured and converted into a U3D-enabled PDF file. To accomplish this, Adobe had to license technology and buy a company, but Adobe soon discovered that U3D did not enjoy very widespread industry support and large converted data sets were really not that much smaller than they began, so why put forth the effort for such a relatively small return.
The second (and current) version, based on Acrobat Version 8, Adobe, however, is a totally different story, largely through the acquisition of TTF, a CAD file format translation company whose technology is a highly compressed, but accurate format called PRC. Adobe incorporated the PRC format and the translators into the new version of Acrobat 3D. U3D hasn’t gone totally away as it remains in the software for creating what Adobe terms “technical documents” and animations, but it’s the PRC technology that does the heavy lifting this time around for model translation for the manufacturing community. Adobe claims that the resulting translated data is so accurate that it could actually be used for machining. We’ll put that claim to the test later.
As with any software product, the UI is literally the first thing you see, and the Version 8 interface of Acrobat has been improved. For example, when it launches, there are a number of options that let you choose the type of workflow that best suits your needs, ranging from creating a PDF and combining model files to launching a Web-based Adobe “Connect” session for shared interactive design reviews.
Overall, the UI is easier to use, more functional, just plain better looking than in the past, and navigation is more straightforward, all primarily due to the fact that the UI is so graphical. The main display area is where the model document is displayed. The UI also contains a model tree with a feature tree, stored views, and object properties. Tabs provides access to multi-pages, bookmarked sections, and digital signatures that have been added to a document.
To get started, all you have to do is click “Create 3D PDF,” and you’re on your way.
Import and Export
Until Version 8, getting CAD data into Acrobat was something of a chore because the company had to rely on licensed and purchased components from other parties. That’s changed, though, and now Acrobat 3D has integrated translators for MCAD packages of all levels, although Autodesk’s Inventor is not part of the mix this time around, but I’m sure that will be addressed and resolved shortly
Some of the supported MCAD file formats include the following applications:
- 3D XML
- CATIA V4 and V5
- Solid Edge (part only)
When importing models into Acrobat 3D, you can select and/or deselect solids, surfaces, wireframes, hidden objects, and construction/reference geometry. There are also options for choosing the file format for storing the model within the PDF, including B-rep, tessellated, and U3D, as well as some combinations.
In its marketing collateral, Adobe claims that after the conversion process was complete, U3D averaged about 10% of the original file size. Tessellation’s were 5% of the original file size and B-Reps should come in around 3% of the original file size (but within 0.01mm tolerance of the original). Reduced file size is important, but just as important is accuracy and maintaining tolerances, and in this release Adobe hopes to prove that Acrobat doesn’t just import geometry, it’s actually capturing valuable information that can be used for manufacturing, as well.
On the other side of the equation, this version of Acrobat 3D can export models to a variety of standard industry formats, such as STEP, IGES, Parasolid, and VRML. Surprisingly, there is no STL export at this time, but I’m sure that will change down the road. Depending on what the output will be used for, each export format has options that can be set with regard to such things as analytics and faces. For at least some level of security, this feature works only when file protection is not attached to a model.
A Simple Example
Although I am familiar with a number of MCAD applications, for the purposes of this review I chose to use SolidWorks 2007 in conjunction with Adobe Acrobat 3D. In this scenario, I’ll be evaluating the two products as a data exchange environment. With this product mix, you actually have three options for converting a SolidWorks model to a PDF. Option 1, with SolidWorks 2007, you can save a model as a 3D PDF directly from within SolidWorks. Option 2 is to open a SolidWorks part or assembly (no drawings, though) directly from within Acrobat 3D. You can also import a SolidWorks model into Acrobat 3D that was saved as Parasolid, STEP, CATIA, Pro/ENGINEER, Universal 3D (U3D), or VRML.
While file size does definitely matter, generally, you will realize better results by importing models into directly into Acrobat 3D. For my evaluation I used several assemblies with part numbers ranging from around 30 to over 12,000. After some experimenting for optimizing the process, for the smaller assemblies, I used files that were exported from SolidWorks as Pro/ENGINEER and Parasolid formats. For the largest assemblies, files were saved directly out of SolidWorks; both as an assembly (.sldasm) and as a 3D PDF.
Conversion times are largely but not exclusively dependent on the assembly size, and optimizing an assembly is an integral part of the process, but more about that a little later. After optimization and conversion, most of my files shrank in size (some considerably) from the originals, but not all. All of the conversion times seemed acceptable and tolerable to me, probably owing to the quality of the TTF translators. You can optimize things by only converting assemblies comprised of unique parts, and not including every fastener, as that really can slow things down. Yes, I could have used simpler parts, but I really wanted to see what Acrobat 3D V8 could do in the real world, hence my using assemblies.
Be forewarned, however, that loading a native SolidWorks file with some conversion settings (such as surfaces) can require an inordinately long time for converting large assemblies, or the application would crash. I did also notice a decrease in conversion performance for larger assembly files. File conversion works best for larger files, but some that were over a threshold not only started to bog down, they actually produced PDFs that were larger than the original files. After a little trial and error, I found that using the PRC conversion setting as the default helped things along quite dramatically.
To further the cause of using the conversion process, saving an assembly from within SolidWorks usually resulted in a PDF that was about twice the size of the original file. The conclusion here is to export from SolidWorks in one of the file formats that Acrobat 3D can import and go from there.
Once converted to PDFs, I was impressed with the section view capabilities and the accuracy of the measurements that were possible. There are a lot of options for views and they can be saved for later use. The rendering and mark-up tools are also versatile and useful.