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AutoCAD

Bug Watch: 3dsout is O-U-T, Out!

6 Oct, 2006 By: Steve Johnson

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More on TIFF troubles and slightly dishonest objects, plus commands and glyphs that go missing in the night.

Don't Get in a TIFF about It, Revisited (2007)
In July I reported that AutoCAD 2007 takes more than 10 times longer to create TIFF files. After further investigation, I have some bad news, good news, worse news -- and the worst news. The bad news is that 10 times is something of an understatement. Some of my tests show that AutoCAD 2007 takes 35 times longer to perform the same task. The good news is that this problem only applies to compressed TIFF files. Creating uncompressed TIFF files actually takes less time than earlier releases -- up to three times faster. The worse news is that it's still several times slower than creating compressed TIFF files in earlier releases. And, finally, the worst news: uncompressed TIFF files are absolutely enormous, sometimes more than 1,000 times larger than their compressed equivalents. That's not Autodesk's fault, it's just the way the format works, but it does preclude the use of uncompressed TIFF files as a workaround.

Helix Honesty Hazard (2007)
AutoCAD 2007's handy new Helix object has a problem: its length property is not very accurate. In a simple case (radius = 1, turns = 1, height =1), I see a discrepancy of about 0.22%. That is, if it should be 6.36226513, it reports as 6.34821765. While this won't present a problem to most users, just make sure you don't use it for any important engineering calculations.

Workaround: None known other than getting out your calculator and working it out for yourself.

3dsout the Window (2007)
One problem that afflicted AutoCAD from Release 13 to 2006 was the 3dsout command's dislike for large models. If the number of vertices exceeded 65535, AutoCAD would just create an empty 3DS file. At long last, AutoCAD no longer has that problem. Unfortunately, it no longer has the problem because AutoCAD 2007 no longer has a 3dsout command -- Autodesk decided that you don't need it any more. Click here to see the reactions of some users who seem to think they do still need it.

Workaround: Recent 3ds Max releases can import AutoCAD 2004 DWG files directly, but there are other reasons users may need the 3dsout command. They may want to convert AutoCAD's RAM-hungry solids (worse in 2007) to more compact and efficient surfaces. 3dsout and 3dsin once performed this conversion, and there is no workaround for that. Users may also need to export to other non-Autodesk programs that support 3DS files but not DWG, but now they can't.

Given that Autodesk's maintenance of this command was practically non-existent for a decade, I hardly think its continued presence in AutoCAD represented a great burden. I'm baffled by its removal, which doesn't appear to have been announced. I will have more to say about command removal and deprecation at a later date.

AutoSnap Broken (2007)
Many of you have ancient LISP routines that cut down on the need for entering common object snaps in certain commands. For example, the following simple command uses the Dist command and enters the NEAr and PERrendicular osnap overrides for you:

(defun C:NP ()
  (princ "\nDistance from near to perperdicular.")
  (command "._DIST" "_NEA" pause "_PER")
  (princ)
)

In 2006 and earlier, the object snaps work in exactly the same way as they do if you enter the above command sequence manually. All of the AutoSnap features (marker, magnet and tooltip) work as expected. In 2007, if the OSNAPCOORD system variable is set to 1, just a plain crosshair cursor appears, leaving the user thinking that no osnap is in use. OSNAPCOORD relates to whether typed coordinates take priority over running object snap, either within scripts or not, although it should have nothing to do with object snap overrides of glyphs.

Workaround: If you can live with OSNAPCOORD set to 0 or 2, you can try that. Alternatively, you may be able to replace your LISP with menu macros, which don't have the same problem.