Topic: dwg file invalid?

[Dinosaur]

Someone may want to try opening it with a HEX editor to see if there is any header information at all.  I tried with Crimson and Notepad and there was nothing visible in the header section.

[Chuck Gabriel]

That is definitely NOT an AutoCAD drawing.  I opened it in a text editor.  If it was a real .dwg file, the first six bytes would be a human-readable code indicating what version of AutoCAD saved the file.  The first six bytes of your file were garbage.

[LE]

There is nothing in there... just blank spaces...

Normally a drawing will start with something like:

AC1015...

[SDETERS]

I do not think the file is a DWG file

[vinnyg]

Apparently something happened from the last time I opened it and saved it until
I tried to open it again before I posted my question. It was drawn in r14 and saved
as .dwg in r14. What possibly could have happened to it in that period......I don't know!

vinnyg

[Dinosaur]

I think a backup file is the only hope for this one.  A HEX editor might be able to create an r14 header but it would be a very long shot.  What happened?  I think there is a very tiny percentage of DOS writes that just fail - sometimes it is a little text file or a temp file that is never needed again and sometimes it nails something important.  In dos days, I would try to save my file, open it immediately and then save again so a good backup could always be found.

[Serge J. Gianolla]

Could it be that the header is scrambled! AFAYK, you [or someone else in the firm] did not try something like DOS_Encrypt from DOSLIB to see what happens?

[vinnyg]

Serge,

No, I'm the only cad person here. I'm not sure what you mean concerning the
DOS function??

thanks for your input

vinnyg

[LE]

Follow the advice Dino... mentioned to you...

Look for the .BAK, or .SV$ - in your temporary folders... appears the only choice... then simple rename the extension to .DWG

HTH

[Greg B]

Follow the advice Dino... mentioned to you...

Look for the .BAK, or .SV$ - in your temporary folders... appears the only choice... then simple rename the extension to .DWG

HTH

Ironic how that is possibly what got the file in trouble in the first place.  Changing the extension.

[Greg B]

I have a questions...what files does autocad make with the drawings.

For instance....Datacad creates 3 files

.aec  - Drawing File
.png  - Thumbnail Pic
.dbk  - Backup File

[LE]

Greg;

Normally if the features on acad are on for AUTOSAVE and the BACKUP copy from each drawing saved.

It will create those extra files... that might help

[Greg B]

Greg;

Normally if the features on acad are on for AUTOSAVE and the BACKUP copy from each drawing saved.

It will create those extra files... that might help

Well now that's not what I'm getting at.  If AutoCAD create's a thumbnail file, it was possible that someone came along and changed the extension of it thinking that it was a backup file.

[LE]

AutoCAD does not work that way...

Usable Drawing files:

DWG
BAK
SV$

DWT
DXF

And maybe other(s) that I dont' recall right now...