to convert pdf to dwg

[Jack_O'neill]

The way I understand it, if it was a scan, or created using a poor PDF creation program.... to represent a letter "A" for example, instead of storing a single font character, it might have been represented as three lines. A letter "O" might be represented as 20 lines, a large arc in the drawing could be hundreds of lines, and so on. It doesn't take long to add up.

 

 

That is exactly what happened. There was a hatch in the architect's logo (part of what I removed before posting) that had 5000 drawing objects in it. That's been the issue with these programs for me. Every time I have ever tried to use one, this is the result. The one Tankman posted earlier is the best one I've ever seen. I'm going to recreate his drawing in Autocad, then make a pdf from it. Then convert it with the software I used on the one I posted just to see what it does compared to Tankman's drawing. Should be interesting.

[Jack_O'neill]

Ok, by way of set up, no I didn't copy every bit of Tankman's drawing. Ran out of time to play. Left off a lot of the text and dimensions, but in reality, if it works on one bit of text it will work on it all. If it screws up one bit, it will screw it all up.

 

Here's what I found. In both programs, neither of them know what a circle is. Makes them into lwpolylines making it impossible to use center or quad osnaps. Neither of them recognize a hatch, and turns it into a bunch of individual lines. That is not unexpected. The program I used put a line through the circle in the center of the big section view that shouldn't be there.

 

Tank's drawing was scaled up 10x. Mine scaled up, but some weird amount. Figured up to be x6.4259259259259....till calculator ran out of digits. Mine also moved the whole drawing away from the 0,0 origin it was set at.

 

They both handled the text much better this time around than they did on the scanned drawing I posted yesterday. Tankman's program made each letter an individual bit mtext, and mine made each line into a separate bit of text. Either way is usable and easily edited as needed. Mine lost the text on the mleader though and scrambled up the line that had the depth symbols on the counterbore.

 

There was a considerable difference in how it converted the lines in the drawing. If you look at the view at the bottom of the page in Tank's drawing, his converter did that line along the bottom of what I'd call the front view in several segments. See below:

 

That's ok, the segments run from the endpoint of one vertical line to the other. At least that's predictable and easy to fix. Mine did it wierd:

 

Why it decided to make those particular segments into one polyline, I don't know.

 

Unlike the 1.5mb file it created yesterday, this one is about 50k.

 

If you just needed something to look at or to drop in and get the main dimensions off of, Tank's version is better than the one I have.

 

If you wanted to model this part in 3d though, neither one is acceptable and you'll have to redraw it from scratch. The way the both handle circles is a major problem.

 

Bottom line is that if you create the PDF from Autocad or Photoshop you get a much better conversion. If you use a scanned drawing, you might as well have an army of 5 year olds copy the drawing for you. If you need to do any kind of serious work with the conversion, you're going to need to redraw it.

 

If you have a drawing that you need to send to someone else, why go to the trouble of making a pdf, emailing that, then the other guy converts it back to a dwg, does what you hired him to do, then makes another pdf, emails it back to you and then you have to convert it again? Why not just send the dwg file in the first place? He can work on it, send it back to you and have done.

 

My conversion is attached if anybody wants to fool around with it.

TANKMAN-Model.dwg

[Dana W]

I am assuming that AutoCAD includes a vector database within the pdf file it creates. This would explain why the pdf files that come straight out of AutoCAD are so stinkin' HUGE, yet convert back to dwg better.

 

I dunno why there does not seem to be enough graphics memory available for my AutoCAD to create clean text in a pdf file. Maybe it hoses itself up when grabbing physical space to calc all that font stuff and mem is already rammed full of vector stuff?

 

Has anyone tried to convert a pdf from TrueView back into AutoCAD? I am not equipped do it, but I would be interested in finding out what, if any, differences might arrise. The Trueview pdf files are much smaller in disk size than the same drawing spit from AutoCAD. I am again assuming that the afformentioned hypothetical vector database may not be included in the TrueView pdf verion.

[rkmcswain]

I am assuming that AutoCAD includes a vector database within the pdf file it creates.

I'm no expert on the PDF file format, but the source application is not a factor. It could be AutoCAD, Microstation, Illustrator, etc., as long as the PDF driver is creating vector objects in the PDF, it should translate back fairly well. It's all a function of what types of objects are supported in a PDF (text, lines, arcs, splines, etc) and to what precision they are stored.

 

Has anyone tried to convert a pdf from TrueView back into AutoCAD? I am not equipped do it, but I would be interested in finding out what, if any, differences might arrise. The Trueview pdf files are much smaller in disk size than the same drawing spit from AutoCAD. I am again assuming that the afformentioned hypothetical vector database may not be included in the TrueView pdf verion.

 

The file size would be vary only because of a different driver and/or different options within the driver (include fonts, include layers, etc). The source application should not matter.