DGN to pdf to DGN

dwy.seah@gmail.com:

 Hi eeryanc,

I haven't tried vectorisation in awhile. Usually involves a lot of cleanup, text recognition etc, so using one of the full blown packages like Descartes or GTXRaster would be where you would end up, normally. Other midrange tools are tractrix or scan2cad pro. 

Thanks for the info!

Jon Summers:

Vectorisation tools have been around for decades. Bentley provide them along with many others. Take a look at the Bentley website

Thanks for the tip.

Jon Summers:

PDF is a red herring. PDF files are containers for different data types. Those types include native PDF vectors (similar to PostScript™) and various raster formats. You don't want to 'convert a raster PDF' because there isn't such a thing — what you want for maximum fidelity is the embedded raster image.

Guess I figured the short-hand would get the point across.   Thanks for taking the time to reconstruct the language just in case any computers were reading.

 Hi eeryanc,

I haven't tried vectorisation in awhile. Usually involves a lot of cleanup, text recognition etc, so using one of the full blown packages like Descartes or GTXRaster would be where you would end up, normally. Other midrange tools are tractrix or scan2cad pro. 

ACAD 2009-10 also allows snapping to vector elements in pdf attachments. See: 

http://www.cadvids.com/video/57ace04ffba31bc/Curtainwall-Tools-for-Autocad-2010-Athena-2010-PDF-Underlay

-for a view on how this can be useful.

The pdf conversion in ACAD 2010 has improved a lot. Hopefully, you won't have to deal with too many rasterised CAD elements.

There were problems with BA's Building/Dynamic Views printing in raster only which is hopefully fixed by now.

eeryanc:

Can anyone recommend a product that converts a raster to a MicroStation supported CAD format?

Vectorisation tools have been around for decades. Bentley provide them along with many others. Take a look at the Bentley website

PDF is a red herring. PDF files are containers for different data types. Those types include native PDF vectors (similar to PostScript™) and various raster formats. You don't want to 'convert a raster PDF' because there isn't such a thing — what you want for maximum fidelity is the embedded raster image.

Regards, Jon Summers
LA Solutions

Can anyone recommend a product that converts a raster PDF (i.e. a document scanned to a PDF) to a MicroStation supported CAD format?  Such a program would need to include a raster to vector converter.  The converters mentioned in this thread (i.e. aidecad) seem to only be able to convert vector PDF to CAD. 

Thanks in advance!

Hello

Some interesting and probably valid comments

The thread did start off though with a request/proposal to be able to convert pdf to dgn. This kind of implies that the person would then want to start directly working with the resultant dgn. I suppose "working with" could mean several things.

There's certainly something to be said for being able to reference in a pdf, using it as background, and then being able to snap to various keypoints. This would be quite different to converting the pdf to a dgn which you could then use as in pretty much the same way as a dgn that you had created yourself from scratch.

Perhaps we are talking about 2 different things here. There are no doubt some improvements that could be done as far as using pdfs as "background information". My feeling is that would still be about as far as it could realistically go for the foreseeable future.

Exporting or producing the pdfs is "losing" a lot of the underlying CAD data/info. Once it's been "lost", putting it back maybe quite a bit harder to achieve. There would need to be quite a lot of work done first with regard to producing pdfs from CAD packages. The pdfs may well not be coming from Microstation. Bentley can't really control how other CAD apps produce pdfs and how those pdfs "behave".

Couldn't comment too much on the situation with FMs and that end of things. Though if they're the sort of firm that uses Microstation, they should really be able to access a set of as built drawings from some CAD package or other, even if those files/drawings are a bit rough/inaccurate. 

Regards

Danny Cooley

Hi All,

I still think you guys are off base big time ! Sorry !

Devlopment effort: Hey if Adobe and Bentley can add geospatial coordinates and presumably deal with geodetic projection tranforms. I think adding some building grid reference points would be easy peasy. Don't forget that Adobe are pretty big outfit and they added 3D and layers to pdf to appeal to the CAD documentation market. These are big commitments, so the CAD market is important to them.

Levels etc would be enough. I wouldn't advocate using pdf as the primary means to exchange CAD data.

Engineering precision: Real world engineering means solving problems and a lot of the time designers need to deal with information that is unstructured, imprecise and sketchy at best. Even if you don't accept this, take facilities management, which will spend on average four to five times the initial build cost of the building. Do you think the FM manager will get a nice precise CAD drawing every time a hairy arsed builder shows up to do some work? You would be lucky if you get a pdf, even if he had CAD he wouldn't want to release it as he thinks that would allow you to shop around more. FM has to be able to use the pdf as an underlay and draft over it, redline it, make notes, file it etc.Low accuracy- no problems. Have you seen what a set of proper surveyed as built drawings look like? Bears very relation relation to the nice clean 'engineered' design drawings, if you want to talk mm precision. Reality check, please?

I also suspect the pdf format because of its 'print' nature, will be more likely to be accessible over the long term (25-50 years).

Hello all

pdf to dgn .... sound interesting (in a way)

Though I would question if this really is a priority ... certainly all the firms I've worked at, we export/archive everything in dgn/dwg and pdf. My understanding is that the pdfs are used to record and "read only" version of the hard copy at a particular stage or point in time.

If we are working with a firm that used Microstation, we get them to send us dgns, if it's Autocad or some other CAD software, then we get them to send dwgs.

The import of data/info from other sources is a much a procedural and project management issue as it is a CAD/software/technical issue.

At the outset of the project you could/should be impressing upon the other companies/consultants what files/formats you want/need to be receiving things in. Whoever has produced the pdfs must surely have some CAD software used to produce the pdfs in the first place. Get them then to provide you with the dwgs. If you require CAD data, then they should be providing it. Why bust your head giving yourself extra work, to make up for their lack of procedures and sloppy project management?

Even if it's the client, and they only have pdfs, make sure they understand that pdfs are "only paper" and that you also require dwgs ("it's the industry standard, not just our choice you understand ........ you want things doing properly don't you?)

I really think you'd be better off sticking with using pdfs as read only/hard copy and if you want CAD data/info, then that should be arranged and worked out using proper CAD applications. You'd be better of putting your efforts in to establishing and improving the import/export to and from dwg that attempting to incorporate pdfs in to the CAD system so that you can then convert them and then work with that info.

Conversion to (full) dgn from pdf sounds like a lot of work (for Bentley) ..... maybe it's not ... but what about cells, hatching, colour fills, level symbology, let's not even begin to consider the different types of 3D elements

My feeling is that this is heading off down a slippery path ............. if you want CAD data, ...... get them to provide it, don't let the fob you off with pdfs .....

Sorry to put the dampers on this, but I would have thought the development effort involved in this could be better put to use elsewhere ...... there are already quite a few issues/settings/tricks involved in importing/exporting dwgs ...... we could do with cleaning up and improving this before we embark on another process, that essentially would just be duplicating what we already have (with then it's own raft of issues/settings/glitches)

My thoughts for now anyway

All the best

Regards

Danny Cooley

Freelance CAD technician

Dominic:

I think you may be blowing these restrictions out of proportion? As Gunnar mentioned, other CAD packages have managed it ...

Gunnar:

Not recommended for things where accuracy and scale is very important. Gregs comment concerning accuracy and scale is to be seriously considered.

I don't think I've been blowing any harder than others that you quote. Don't confuse restrictions with accuracy or repeatability.

Dominic:

With a fair wind and a bit of luck and a little optimism?

As an engineer and designer, I prefer analysis, diligence and thoroughness. But I'm always optimistic.

Regards, Jon Summers
LA Solutions

Hi Jon,

I think you may be blowing these restrictions out of proportion?

I think Bentley is showcasing georeferenced pdfs this year, so supplying an origin is pretty trivial really if you can influence the right people at Adobe, and not just have to work within the given API. 

As Gunnar mentioned, other CAD packages have managed it, so with a fair wind and a bit of luck and a little optimism?

PDF lacks precision

Dominic:

I would have thought that -eventually- MicroStation would reference PDFs as vectors where possible, not as raster for speed/resolution.

Phil Chouinard:

PDF is not a pure vector format ...

GregC:

I often use Adobe Illustrator CS3 to open a pdf, save as dwg and copy into a dgn. Not recommended for things where accuracy and scale are very important.

Remember that PDF is an acronym for Page Description Format. It is not VDSCPFAEI (an acronym for Vector Data that can Safely Be Converted from Page Format to Accurate Engineering Information).

A PDF may contain vectors, rasters, or both. PDF vectors are described by integer coordinates of sufficient resolution to draw into a paper page size, although a source tells me that  later versions of PDF do use a floating-point vector format. They don't have an origin, other than the top-left corner of the paper page. They don't have a scale — they draw into a page-sized space.

Those constraints limit what anyone might do when converting a PDF to DGN. If you don't supply an origin and a page-to-DGN-model scale & rotation, then the imported vectors will be worthless.

Furthermore, as the vectors are converted from PDF integer to DGN full precision there will be rounding errors. The danger here is that the converted vectors are perceived to be correct & accurate because the computer says so. As an engineer I would be loath to accept information that is presumed to be correct when analysis tells me that, most probably, it is incorrect.

Regards, Jon Summers
LA Solutions

Hi Mathieu,

This is a shame. Can this be changed easily ? Would this be a plaform task ?

I would have thought that -eventually- Mstn would reference pdfs as vectors where possible, not as raster for speed/resolution. 

Regards

Dominic

dwy.seah@gmail.com:

Here's an idea: Mstn already references pdfs. Maybe it should be able to convert the pdf elements into dgn elements when it is asked to 'merge' the ref into the active file.

Unfortunalty, the referencing of  a PDF to a model in MicroStation is a bug and the conversion won't work because the PDF is open as a raster.

Thanks,

Mathieu

GregC:

I often use Adobe Illustrator CS3 to open a pdf, save as dwg and copy into a dgn. Only thing I have to do first in Acrobat to make this easier is extract that page from a multipage pdf.

Not recommended for things where accuracy and scale is very important. I generally have to pick a couple of dimensions and rescale the converted graphics back to 1:1.