3D printing and human skill
This National Geographic video about 3D printing exemplifies the worst kind of gee-whiz reporting. Just scan a crescent wrench, print it, and bingo, you’ve copied a real tool with moving parts!
A commenter notes differences between the copy and the original and concludes:
If the real wrench was simply scanned, this would not have happened. A human has built the design data.
3d printing is cool, why do they feel they have to lie about the input method?
The input method is, of course, 3D CAD. From the product brochure for the printer:
Z Corp.’s 3D printing technology leverages 3D source data, which often takes the form of computer-aided design (CAD) models.
Gee-whiz reporting insults our intelligence and trivializes its subject matter. It’s fun to imagine a magic replicator, but it’s more interesting to know about the human/computer interaction that makes real replication possible.
Once I wrote a review of a dozen 3D CAD programs for BYTE Magazine. The benchmark was a model that I commissioned an architect to design. We called it the BYTE Pantheon and it looked like this:
My job was to construct that model in each of the dozen CAD programs. It was hard! That was partly because I had no prior experience with CAD software. But it was also because each program had its own way of using 2D gestures to manipulate 3D objects. That was my main takeaway from the project. There wasn’t (and I think still isn’t) a standard suite of gestures. Even if there were, and even (I suspect) when you can use 3D gestures, it would still be hard because you are making a precise description of a complex object. Wikipedia calls CAD an “industrial art” for good reason. Models with the same functional qualities can differ in terms of style and sophistication. Those differences come into play when the model is shared and modified. Or so I imagine, anyway. I’m not a 3D modeler but I understand 3D modeling to be a process akin to programming.
A friend of mine, Gary Spykman, describes himself as a designer, furniture maker, and artisan. He has also become a 3D modeler, and uses SketchUp to explore his designs and render them for clients. A couple of years ago, Gary designed and built what he calls his cabana. Here it is as designed in SketchUp, and as built in Gary’s back yard.
When I saw what Gary was doing in SketchUp I was inspired to try using the program for some simple needs of my own — to visualize my geodesic tomato suspension dome, and more ambitiously to visualize a remodeling of our kitchen. And you know what? It was just as hard as I remembered! If you do this stuff for a living, as Gary does, then it becomes second nature. But if you only do it occasionally, like me, you’ll be impressed every time with the level of skill required to precisely describe an object or a scene.
Like the commenter on YouTube I have to ask: why lie about this? National Geographic’s gee-whiz reporting doesn’t just fail to inform. It also fails to celebrate the synergy between computational power and human skill that makes 3D modeling so fascinating.
Jon, et al, I’m very surprised by your comment given the context of the National Geographic show. While you are correct in noting the variances between the scanned and printed wrenches, The objective and message of that particular portion of the video was to demonstrate how easy it is to make changes to a scanned part using 3D software (we were changing the color of the part at the time). Indeed I’m sure you all know that this is the most common way that engineers work with scanned parts – get it into 3D software first: then stretch this, add that, print and see if you’re satisfied with the results – a basic iterative design process. We are strong proponents of iterative design because that process produces better results. Even if no changes were made to the basic structure of the tool, it is very common for engineers to modify a scanned file, for example, to complete the internal workings of a moving part that might not be visible to the scanner. Contrary to your claim, It’s not deception for marketing purposes, just normal processes very familiar to users of all 3D scanners. Obtaining a near-exact replica of an object is entirely possible even though that was not shown in the video. For example, our ZScanners have an XY accuracy ranging from up to 40 microns for our high-end scanner to up to 80 microns for our entry-level scanner. The resolution ranges from .050 mm in XYZ for our high-end scanner to .1 mm in Z for our entry-level scanner. In fact, our scanner customers are using our scanners for inspection applications where accuracy is mission critical, as well as reverse engineering and other applications (see Mackay Consolidated inspection case study: http://www.zcorp.com/en/Company/Customers/Case-Studies/Mackay-Consolidated-Industries/spage.aspx).
The complaint by the YouTube commenter, with which I agree, is not that there were differences between the scanned and printed part. Nor that ZCorp was in any way deceptive. My beef is with the videographer who made choices that imply an unrealistic degree of automation.
it is very common for engineers to modify a scanned file, for example, to complete the internal workings of a moving part that might not be visible to the scanner
Exactly. And correct me if I’m wrong, but I’m sure that even when the scanner can see everything the model will typically require human attention. That’s not a bad thing. On the contrary, the iterative computer/human interaction is a wonderful thing. What irks me is that the videographer chose to suppress it.
You are correct in that some human attention would be needed. The National Geographic folks were not at all trying to be deceptive; they were trying to convey the process in a way that would be understandable to the bulk of their audience and within the timeframe they had available for the segment.
I do understand the constraints. But in the time allotted I could have produced a version of that video that would have told a realistic version of the story that would be no less understandable or impressive — and arguably more so.
If/when ZCorp creates something that teaches people how the process really works, I would love to see it.
=15Webcast “Can a Car Maker Really Deliver Mass Customization” (4th from the bottom) and How A Leading Aftermarket Auto Parts Manufacturer Cut Product Development Time By 40-Percent (bottom of page)
Demonstration of ZScanner 800 =M3zkUSwEBV4
ZScanner 700/800 video: http://www.zcorp.com/en/Products/3D-Scanners/ZScannerandtrade-700/spage.aspx (click on “video” in right column)
If you need additional information, please don’t hesitate to let me know.
To convert scan data to a parametric solid model (it does come out of our ZScan software as polygons) we typically recommend looking at the products from Rapidform and Geomagic. Both wonderful tools to do this job. You asked to see that step in the process and searching on YouTube will result in several videos like this one:
I hope that helps…
Jon, The processes described in the two Webcasts are those used by those two customers, described by them in their own words. I linked to more than 2 videos, perhaps the others provide you with what you’re after. If not, I’m afraid at this point, that’s all I have. If you’re looking for a more detailed, technical description, we can certainly provide that as well. We provide videos based on our audiences. When someone needs something more detailed and technical, we generally provide them with a one-on-one, live demonstration. Please let me know if you’d like us to arrange such a demo for you.