Drawing Security - PDFIMPORT 2

[phamENG]

Quick question. I feel like it's been addressed by my search engine magic isn't working right now.

This scenario used to happen to me when I was working at my old job: Drawings are produced and sent to the client as a PDF. For a long time I got really confused how details that were on my drawings end up on steel shop drawings. And I don't mean they redrew it. I mean I can see their details with their formatting, and there's my detail with it's formatting as though it was lifted off of my sheet. And not a cut and tape/paste sort of thing. They generally remove the items that are of no concern to them. So they were getting it...somehow. (And this is on jobs where CAD files were NOT sent out).

Fast forward to now, I'm running my own show, and I want a little better security. I can't lock down the PDFs - too many file combinations and plan review stamping requirements down stream. I've tried and hit walls with clients and municipalities.

I think I figured out how they do it. PDFIMPORT in AutoCAD. If the PDF has the underlying information, AutoCAD can extract it and reconstitute a CAD drawing that can be manipulated. Short of printing and rescanning drawings as images, anyone know of a good workaround to make sure the PDF is PDFIMPORT proof?

 

[driftLimiter]

I am pretty sure there is a way (depending on which PDF plotter you use) to eliminate the information that is imported via CAD. I say this cause I have seen two predominant types of PDFs for plans. Some pdfs have tons of info related to the CAD it was output from. For example you could hover over lines in the PDF reader and some info regarding its CAD origin would pop up contextually. However there are some other PDFS maybe just flattened ones, that are 'dumb'.

I'm speculating here but thats my take on it. In today's world it will be hard to eliminate all of the leaks of info. Someone could just snip your detail from the PDF and paste it on their drawings. I guess thats the reality of our current paradigm.

 

[Brad805]

To make you very sad push "shift G" in bluebeam. You can snapshot any .pdf exactly and re-paste that .pdf where ever you want. Once you paste/flatten the image I can crop out whatever text I want. If you want to add text, you can make the details look nearly original so long as the original drawing used an MSFont. I only use it for checking/discussing details. I freaking love it. I can paste enlarged details on our clients dwgs, adjust the scale as necessary, and quickly check embed locations.

There are quite a few PDF conversion tools nowadays, but I am surprised how few know how to do it. I recently had some shop dwgs from an OWSJ supplier where I am sure they had applied different scale factors in the X and Y direction when they created the .pdf file. I imported the dwg and fiddled with it for quite some time and could not get the dimensions correct. That is difficult to work around. I think scanning is about the only option since that removes the raster data.

 

[Celt83]

Print to a raster based pdf instead of vector. The vector based option retains vertices and lines, layers, etc. so it will scale perfectly if the PDF is resized. the raster option will produce a lossy image based pdf. There is decent software out there nowadays that can convert the raster version to Autocad by processing white vs black pixels so still won’t prevent detail lifting but makes it a little harder.

I'm making a thing:

http://www.thestructuraltoolbox.com

(It's no Kootware and it will probably break but it's alive!)

 

[3DDave]

Import into Adobe Photoshop or GIMP and save as a PDF. It will be flattened to a bitmap but still be readable by Acrobat Reader, etc. Choose 300 dpi or somewhat more, but don't go too high or the file size gets ridiculous. Very important to note - the default is 24 bit/pixel color which many applications will happily retain - force them to 1 bit and the file size will be considerably reduced.

 

[IRstuff]

Used to be that you could print from Adobe as a bitmap, which flattened everything; barring that, you can export as an image file and then turn it back into PDF.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[phamENG]

Brad - Yep, I do the same thing. But fortunately for this case I'm a terrible drafstman and my notes tend to be scattered around my details. So if you try to cut something out, it's obvious. I'm not so worried about somebody stealing my details as I am wanting to prevent lazy detailers from lifting the details rather than doing the work of figuring out the specifics for themselves. (I'm not saying all detailers are lazy...I've worked with a few very diligent and talented detailers...but I've also worked with some really sloppy detailers who didn't even read the notes, just copy and pasted.)

Celt - I tried that once before, but I was still able to convert it in ACAD with IMPORTPDF.

3DDave/IRstuff - your ideas are pretty similar. I like it. I might give it a go. I use Bluebeam, and I can save the PDF as a bitmap image file and then resave it as a PDF. I'll have to do a test and see if Bluebeam somehow retains the data under the image.

I know nothing will stop somebody who really wants to do it...but a few road blocks will help keep the marginally honest a little more so.

 

[JStructsteel]

How or why does it matter? Are they using it maliciously, or just being economical? I send my CAD files all the time. 1, they can redraw it they want. 2, they cant change my stamped drawings. 3, makes for a better shop drawing, and hopefully a correct detail.

 

[dold]

Here's how we do it:

 

[phamENG]

dold - I use similar language. Though yours is a bit more succinct. I may plagiarize a bit if you don't mind.

JStructsteel - I know this is a point of contention. I know not everyone agrees. Are they being malicious? No. Are they being more economical? In some respects, perhaps. But for me an important point of shop drawings is for the contractor, fabricator, and erector - through the work of a detailer - to demonstrate a thorough understanding of the intent of the design. If they simply regurgitate my work onto their drawing, they aren't showing any sort of understanding.

 

[kissymoose]

I agree with Celt83, print to raster instead of vector. So when you zoom in you see pixels.