Convert, compress, and collaborate on 3D models with PDF

Adobe Acrobat 3D Version 8 (www.adobe.com/acrobat3d) includes features that are likely to knock your engineering socks off. For starters, the software includes an internal file format called PRC that generates highly compressed files. For instance, it can turn a 33-Mbyte Pro/Engineer model into a 200-kbyte PDF file, while retaining the accurate 3D geometry, colors, assemblies — and even the product-structure tree that displays how parts and assemblies relate to each other.

You are probably familiar with Acrobat as software for authoring PDF documents, and the free, downloadable Adobe Reader that lets individuals view and interact with PDFs. Acrobat 3D Version 8 can also export STEP files. The software also allows exchanging product-manufacturing information (PMI) along with accurate 3D geometry.

Interestingly, the PDF specification has been published since 1993. This means anyone can take the spec and develop software that outputs PDFs. The company also plans on publishing the PRC specification.

These features of the latest version of Acrobat 3D are intended to help engineers collaborate with users who might not have the same CAD software — or even have a CAD system at all. The concept: The more eyeballs looking at design ideas, the more likely design flaws will be caught early on.

Despite its capability, Acrobat 3D V 8 is easy to use. A new, intuitive Getting Started page directs you to common tasks such as Create PDF, Combine Files, Export, Create 3D PDF, and Review & Comment. For example, click on Create PDF and a page opens with several helpful options. Ever tried to print a Web site page only to have one side of the text chopped off? Select the handy Create PDF from a Web site option and type in the URL of interest. Once the page is downloaded, save and print it as a PDF. The format ensures the whole page will print.

Of course, common tasks are also available from the toolbar at the top of the main Acrobat window. Combine Files, another helpful task, lets users generate a single PDF from various sources such as spreadsheets, business documents, and CAD files. A wizard lets users browse for, select, and then add files to a Combine Files window, in the required order. The software then merges the files in that order into one PDF.

And when it comes to 3D, users can embed CAD models into PDFs with a special tool or import them by converting the files. It's helpful to note that Acrobat 3D stores 3D data in PDF as either the PRC, or the Universal 3D (U3D) format, the latter of which supports textures, lights, and animations, depending on user-selected settings. The conversion method allows maintaining the original file structure, including part names and hierarchies.

Users opening a 3D file in Acrobat 3D will see a Conversion window pop up that lets them select conversion options such as PRC B-Rep, PRC Tessellation (Faceted), or U3D ECMA 3. Files saved to PDF using a PRC B-rep setting can translate the geometry to standard formats including IGES, STEP, Parasolid, and VRML. The geometry data can be exported for use in CAD, CAM, and CAE applications (PMI is not included in the exported file).

Because PRC compresses files to a fraction of their original sizes, PDF can be a handy archiving mechanism, storing precise CAD data in small spaces, rather than the gigabytes of native files. Large assemblies can be stored in a highly compressed fashion to reduce computer time and memory.

Using the 3D tool to embed CAD models in PDF documents is a nifty way to make animated assembly manuals. The software lets users add JavaScript files to the 3D model to create interactive and animated documents. Users can also add JavaScript to illustrate the effects of one component on another, simulate a camera moving around the model, and activate other files or models. For instance, a 3D design might be displayed in 2D, or as a wire frame.

Hovering the cursor over any 3D image in PDF brings up a Click to Activate bar that includes tools such as Rotate, Pan, and Spin. Other tools let users measure a model, see the history tree, change the background color, and toggle between different rendering modes.

For collaboration, users of Acrobat 3D V8 can limit access to PDFs by setting passwords and restricting certain features, such as printing and editing. Select Comments and then Enable for Commenting and Analysis to let recipients with Reader Version 8 participate in document reviews by adding comments and using measurement and cross-section tools directly on 3D objects.

The software provides two ways to collaborate. Shared reviews are suitable for groups that work behind a firewall and access a remote server or network folder. Published comments are saved to the server and the local hard drive, and Version 8 synchronizes comments between these locations at regular intervals to download the latest comments and changes. The software informs the session initiator of all recent review activity each time the PDF is opened. However, shared reviews do not support commenting on 3D files.

Collaborating by e-mail, on the other hand, does allow reviewing 3D models. First open the document of interest, click on Review & Comment, and use commenting tools such as Sticky Note, Text Edit, Callout, and Cloud. Then save the file and select Attach for Email Review. A wizard walks you through selecting the PDF, inviting reviewers, and sending the e-mail invitation. Recipients using Adobe Reader can respond selectively to your comments or add their own. Version 8 then tracks and merges all the changes.

The software comes from Adobe Systems Inc., 345 Park Ave., San Jose, CA 95110, adobe.com