cca13@seq1.keele.ac.uk (G.D. Pratt) (06/28/90)
Can anyone point me in the direction of software that can create "DXF" format files as used by AutoCad? I have some files provided in CCITT group 3 format which I can convert via PBMPLUS, libtiff and/of FBM to lots of other things. But I have a punter who wants them in this DXF format for AutoCad which I know nothing about. Any help appreciated... I think that's him at the door now! cheers, gerry -- gerry pratt - workstation support - university of keele email: cca13@uk.ac.keele.seq1 * tel: 0782 621111 x 3290
tj@gpu.utcs.utoronto.ca (Terry Jones) (06/28/90)
Well Corel Draw 1.2 will take bitmap files and convert them to object oriented files with their CorelTrace program. Then Corel Draw itself will export the file to DXF format. DXF files are object oriented. Group 3 FAX and PBM are bitmap formats. There is more to it than just a conversion such as from tiff to group 3 or whatever. First you have to decide which groups of dots make an object, then you can write an object form of things. This is NO EASY TASK!
deke@ee.rochester.edu (Dikran Kassabian) (06/29/90)
I was tempted to specify a Followup-To:. but couldn't figure out exactly what would be appropriate. Those who followup to this message may want to do so. In article <1990Jun28.143847.9013@gpu.utcs.utoronto.ca> tj@gpu.utcs.utoronto.ca (Terry Jones) writes: >Well Corel Draw 1.2 will take bitmap files and convert them to >object oriented files with their CorelTrace program. [...] > >DXF files are object oriented. Group 3 FAX and PBM are bitmap formats. >There is more to it than just a conversion such as from tiff to group 3 or >whatever. First you have to decide which groups of dots make an object, then >you can write an object form of things. This is NO EASY TASK! No easy task, indeed. In fact, I'm convinced that it can't be done in many cases without imposing heuristics that will be situationally appropriate. I'm interested in any published works that address these issues, and especially those that discuss algorithms. BTW, its my impression that the Adobe product "Streamline" does much the same thing, in that it takes bitmaps as input, and generates postscript line, curve, fill, and point instructions as output. I may well be wrong about that, so I'm hoping that someone who has used this product can comment, and I invite those with insight into this general topic to enlighten me, and tell me that the problem isn't as intractable as I now believe. :-) ^Deke Kassabian, deke@ee.rochester.edu or ur-valhalla!deke Univ of Rochester, Dept of EE, Rochester, NY 14627 (+1 716-275-3106)
graham@advsys.UUCP (Graham Underwood) (06/29/90)
In article <417@keele.keele.ac.uk> cca13@seq1.keele.ac.uk (G.D. Pratt) writes: > >I have some files provided in CCITT group 3 format which I can >convert via PBMPLUS, libtiff and/of FBM to lots of other things. >But I have a punter who wants them in this DXF format for AutoCad >which I know nothing about. > Group 3 defines a raster compression standard. DXF is a CAD drawing file format, i.e. vectors, symbols etc. I think you may be dead in the water on this one. Salvation may however come in the form of CADOverlay which is an add on product for AutoCad. This allows you to display a raster image as a backcloth in AutoCad. Graham.
cameron@kirk.nmg.bu.oz (Cameron Stevenson) (07/04/90)
From article <1990Jun28.143847.9013@gpu.utcs.utoronto.ca>, by tj@gpu.utcs.utoronto.ca (Terry Jones):
> DXF files are object oriented. Group 3 FAX and PBM are bitmap formats.
I think it incorrect to call DXF files object-oriented. Autodesk has been
using this term for a while now to distinguish AutoCAD from painting
applications. What they SHOULD be calling AutoCAD (and what you should
therefore be calling DXF files) is vector based. As you have correctly
stated, FAX, GIF, and heaps more are bitmap (or pixel) file format - ie.
this dot is black, the next one is white, and so on...
Vector based file formats store the definition of a line (or any other
graphical element) - ie. this line starts here, is so thick, and goes there,
and so on...
Object-oriented files (or more correctly, the data created by object-oriented
systems) store both the data (ala pixel and vector files) AND some code
within the object - ie. I am a line, and when I receive a message to display
myself, I will start here, and end here, but if I recieve a message to
tell how long I am I will return a number, and so on...
Sorry to be picky, but it annoys me when Autodesk call AutoCAD an
object-oriented CAD package. It is true, there are some object-oriented
CAD packages around (most in experimental stages), but AutoCAD is NOT
one of them. The implication from Autodesk (I think!) is that AutoCAD
has something that it's competitors doesn't, and most CAD purchasers
don't know enough about the subject to question them.