Vol. XX, No. 1
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Spring, 2007

Publishing 3-Dimensional Objects

Harrison Eiteljorg, II

Publishing in 3D sounds like some kind of a silly dream. Imagine looking at an image of an object on a piece of paper and rotating it so that you could see the object from multiple points of view. That may seem preposterous, but Adobe has managed to create a digital version of that imaginary 3D paper publication - a PDF file with 3D objects. Acrobat Reader can now show a rotatable 3D image on screen from a PDF file. Using Acrobat reader on any computer (I have been able to view and rotate on MACs and PCs), anyone can have the benefits of seeing a 3D object as a truly three-dimensional object. To be sure, one must have Acrobat Professional rather than just the Acrobat Reader at the moment, but version 8 of Acrobat Reader will be able to display the 3D objects without other software as an aid, according to Adobe technical support personnel.

Adobe makes a 3D version of Acrobat (a stand-alone product called Acrobat 3D, which is apparently only available for Windows) to create a PDF file containing a 3D version of an object. This capability is included in Acrobat Professional version 8, which has just gone on the market, but a new version of Acrobat 3D will have additional features not included in Acrobat Professional. (These 3D capabilities will apparently exist only in the Windows version of Acrobat Professional, and there will remain only a Windows version of Acrobat 3D.) I was able to download a trial version of Acrobat 3D (before Acrobat 8 had become available) to test the possibilities. Based on my reading of the information on the Adobe website, I have concluded that the 3D features were at least partially developed by SolidWorks, a CAD company that produces software only for Windows. That may explain why the Acrobat product only has these 3D capabilities in the Windows version.

This is one of those products that is all but impossible to describe. It is best described by showing what it can do; so there are two examples of 3D objects in the PDF document that may be downloaded here. There are two blocks in 3D. One is a block from the Propylaea, modeled as a part of the CSA Propylaea Project. The other is a ceiling coffer similar to those in the Propylaea but not modeled as a specific ceiling coffer but as a paradigm.

After you have downloaded the PDF and opened it, experiment by grabbing and rotating the objects, changing the lighting, and so on. The possibilities are surprisingly extensive and effective. Users with Acrobat Professional, not just the reader, will also be able to retrieve dimensions, annotate the model, and create cross-sections.

There are also significant limitations. The process seems to work only with solid objects, not lines or surfaces. In fact, I was unable to get all solids to transfer but could not determine the nature of the problems I experienced. Surfaces that are on a solid object would not transfer. The third page shows drawings of the Propylaea block as exported from AutoCAD. Those two drawings show what the original drawing file included that did not survive the transfer process -- the AutoCAD hatching to indicate anathyrosis, damaged surfaces, and cuttings. (This probably reflects SolidWorks' participation ass well, since its products are based on the use of solids, not surfaces.)

Both blocks in the PDF file were modeled in AutoCAD and brought into Adobe Acrobat 3D. The process was not difficult, but it required a specific version of AutoCAD's graphics drivers, a limiting factor. To be specific, making the 3D PDF requires the OpenGL driver version that is part of AutoCAD 2006, and I was unable to make the process work with AutoCAD 2007, which has a later version of the OpenGL driver. (I was using my Intel-based MAC laptop running Windows and both AutoCAD 2006 and AutoCAD 2007.) The red color of the objects also seems to be something that the process added to otherwise black objects.

I had little luck with lighting the objects in AutoCAD and bringing them into Acrobat with the lighting choices I thought I had made in AutoCAD. The lighting effects in Acrobat, however, made up for that to a degree, providing better views than the imported lights. A variety of choices is available in Acrobat.

I have not been able to test this as fully as would be most desirable because, having just learned about it at the CAA meetings in Berlin at the beginning of April, it seemed important to bring to our readers' attention without delay. I will test it more thoroughly and report further. As it stands, however, it already points to a promising capacity to show real-world objects as the three-dimensional entities they are. Stay tuned.

-- Harrison Eiteljorg, II

For other Newsletter articles concerning CAD or the use of electronic media in the humanities, consult the Subject index.

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