DWG Deciphered?
23 messages in this thread
DWG Deciphered? — declared parent_msg_num=(none), resolved parent_id points to #(none)
I'd love to know the least little bit about the format of DWG files. Several
companies have deciphered the format. Is anyone talking about it? Any clues
would be appreciated…
(I know, you're supposed to use DXF.)
#132253-DWG Deciphered? — declared parent_msg_num=132253, resolved parent_id points to #132253
J,
Those that have deciphered it are charging for the information.
Dennis
#132442-#DWG Deciphered? — declared parent_msg_num=132442, resolved parent_id points to #132442
I'm well aware of that. But really, they're not charging for the information,
they're charging for their implementation. It's not as if they've got the
details of DWG printed in a little book that costs $1000.00. They've got link
libraries you can use on the PC and maybe one or two other platforms… or
less.
Out of all the smart guys in the AutoCAD marketplace, you can't tell me that
only one or two companies have deciphered DWG, and that in the several years
since they've figured it out, that no one's talking. Didn't Microstation just
announce that they read and write DWG now, too?
Hey, I've got to ask around, or I'll never know. 🙂 My company makes
InterChange Plus, a 3D file format translator program. Yes, having DWG would
be quite a feather in our cap. Yes, we'd be glad to pay to find out.
#132512-DWG Deciphered? — declared parent_msg_num=132512, resolved parent_id points to #132512
There's a big difference between "deciphering" the DWG file for your own
purpose and marketing a DWG access library. Most people who access DWG files
are just trying to get at a small part of the file.
BTW, Intergraph licensed the source from Marcomp.
#132566-#DWG Deciphered? — declared parent_msg_num=132566, resolved parent_id points to #132566
I didn't know that Integraph licensed Marcomp's code. How did you learn that?
#132626-DWG Deciphered? — declared parent_msg_num=132626, resolved parent_id points to #132626
Intergraph sent a flier about a year or so ago. I also know MAtt Richards.
#132665-DWG Deciphered? — declared parent_msg_num=132665, resolved parent_id points to #132665
Who is Matt Richards?
Also, in a previous message I disparagingly said that Marcomp only supported a
few platforms with link libraries. No one corrected me, but my sense of
honesty requires me to state that thaey do support a half-dozen platforms.
#132702-DWG Deciphered? — declared parent_msg_num=132702, resolved parent_id points to #132702
Matt Richards wrote Autodirect and a few other utilities. Thus the name MARcomp
as in MAtt Richards. (he's also from MARyland) Don't you ever get on CIS
Matt???
#132702-DWG Deciphered? — declared parent_msg_num=132702, resolved parent_id points to #132702
Sirlin's CAD++ ENGINE provides full DWG read/write support for DOS, Extended
DOS, ADS, Windows, and Unix platforms, including Sun, HP700, SGI. RS600,
Ultrix, NT, and Mac are on the way.
Regarding cost, if you just want to access the DWG information, our read-only
library only costs $495 and no royalties. This includes lots of good tech
support.
–Jonathan.
#132626-DWG Deciphered? — declared parent_msg_num=132626, resolved parent_id points to #132626
Intergraph announced in their press release over DWG that Marcomp supplied the
library. There was some discussion on the Forum whether Marcomp would loose its
Registered Autodesk Developer status for that–they didn't. However, it took
Bentley Systems a year to produce the DWG-write code to work between
MicroStation and the Marcomp library.
#132975-DWG Deciphered? — declared parent_msg_num=132975, resolved parent_id points to #132975
Why would Marcomp lose developer status? For supporting an unsupported file
format? If they released proprietary info, I would understand… but they
deciphered the undocumented. Are you saying that Bentley had troubles with
Marcomp's code?
#133021-DWG Deciphered? — declared parent_msg_num=133021, resolved parent_id points to #133021
I guess if you haven't been following the ebb and flow of the forum over the
last couple of years you wouldn't understand the political implications of an
Autodesk Registered developer selling access to the DWG code to AutoCAD's #1
competitor.
#132512-DWG Deciphered? — declared parent_msg_num=132512, resolved parent_id points to #132512
>> It's not as if they've got the details of DWG printed in a little
book that costs $1000.00. <<
If I'm not mistaken, there used to be a product (circa 2.62) called Auto
I/O which was printed in a little book and cost a couple hundred. (Not
much use now but I still wouldn't mind getting my hands on it) <g>
I never saw it and don't recall who published it but remember that it
was reviewed as a written explanation of the DWG format.
I've heard it _rumored_ here that a new book is coming out but haven't
seen anything yet.
Well… I've got it and can't figure out what to do with it. 🙂
Any ideas?
-Chuck
#132596-DWG Deciphered? — declared parent_msg_num=132596, resolved parent_id points to #132596
"Well… I've got it": what exactly have you "got"?
#132625-DWG Deciphered? — declared parent_msg_num=132625, resolved parent_id points to #132625
What I've got is the source for my own library which reads DWG files using the
familiar ADS function interface. I've used it to develop a standalone DXF
translator and am working towards a windows viewer. My guess is that Autodesk
will eventually provide an external API but will not document the DWG file
itself. As Jonathan mentioned, it can get "quite hairy" and, IMHO, would be a
nightmare to support.
I would be quite interested in seeing my code put to good use and hope that I
may be able to help you out in some way.
-Chuck
#132596-DWG Deciphered? — declared parent_msg_num=132596, resolved parent_id points to #132596
I believe the book was co-authored by Fred Jones, of the late Eclat. He is now
with E-BOOK. If you can find him, he'll be able to say where to get the book.
#132512-DWG Deciphered? — declared parent_msg_num=132512, resolved parent_id points to #132512
J.
I'm sure you'll be contacted by somebody now that you say you're willing to
pay for it.
Dennis
#132640-DWG Deciphered? — declared parent_msg_num=132640, resolved parent_id points to #132640
I guess that means it's not such a secret, then? 🙂 Also, someone mentioned
an old v2.6-era book that discussed the format of DWGs. Had anyone heard of
that book, or do they have a copy they could lend?
#132703-DWG Deciphered? — declared parent_msg_num=132703, resolved parent_id points to #132703
Sorry, never heard of it 'til now.
Dennis
#132253-DWG Deciphered? — declared parent_msg_num=132253, resolved parent_id points to #132253
>> I'd love to know the least little bit about the format of DWG files. Several
companies have deciphered the format. Is anyone talking about it? Any clues
would be appreciated… <<
Being from one of those companies, I'd be happy to talk about it. The DWG
format mostly parallels the DXF, in that there is a header section, tables
section, blocks, and entities. In general, you can take a dwg file, convert it
to dxf, and convert it back to dwg without losing any information. That means
that both formats contains the same information, just in vastly different
formats.
DWG is a binary compressed file. The specific implementation varies from one
release of Autocad to the next, and can get quite hairy. There are CRC
checksums throughout the file for error checking, and some information is
stored twice for redundency.
If you want to access DWG files directly, you would be better off using a 3rd
party library. My company produces such a library, called the CAD++ ENGINE,
which is available for DOS, Windows, and Unix platforms. Sirlin can be reached
at 603-437-0727.
–Jonathan.
#132756-DWG Deciphered? — declared parent_msg_num=132756, resolved parent_id points to #132756
Thank you for your comments. As I said in one of my other postings, my company
makes a 3D translator. We're at the fringes of the CAD market, the bulk of our
customers are shuttling data between what are more commonly called "3D"
programs, used for video and animation. A lot of these people have clients who
can supply data in DXF form, but DWGs would be nicer for file-size and
convenience. I've hesitated to consider a third-party link library for this.
First, we have a version of our program for the Amiga. The Windows version will
be out this fall. We're also porting to the Mac. So for two out of three
platforms that we *need* to be on, I can't get a DWG library. And I'm not even
sure if (say) Marcomp's library is available in Metaware's 32-bit Windows form,
as opposed to 32-bit DOS. Is your library in this form?
Having dealt with third-party libraries in the past, I know what kinds of binds
can occur. Without source, my company's reputation is at the mercy of another
company.
#132885-#DWG Deciphered? — declared parent_msg_num=132885, resolved parent_id points to #132885
Marcomp's library is available in Metaware's 32-bit Windows form>>
32-bit libraries are available, as well as 16-bit. They work for both DOS and
Windows. (Although you never know when/if Windows will be a separate license)
I expect things will get exciting when R13 hits, but I also expect Mcomp &
Sirlin will do whatever it takes to make it work. I wouldn't worry about
getting 'burned'.
#132885-DWG Deciphered? — declared parent_msg_num=132885, resolved parent_id points to #132885
J.–
1. The Sirlin CAD++ ENGINE libraries definately support Metaware on DOS. We are
working on a Mac port now. Your's is the first request I've seen for Amiga.
2. Perhaps you could just use a DWG2DXF utility to convert drawings before
importing them into your program using DXF. Sirlin's DWGxDXF utilities go both
ways for $99.
3. If source is an issue, we can arrange an escrow account. We've done this
before.
–Jonathan.