Yearly Archives: 2017

Undo, U, Redo, Erase, Oops differences explained

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It’s been a while since I posted any beginners’ tips, so here goes.

There are several commands in AutoCAD to do with reversing things you’ve done. They are in some cases subtly different and this can confuse newcomers. Here’s what they do:

  • U – reverses the last command you used.
  • Redo – reverses the last U or Undo operation you performed, if that’s the last thing you did.
  • Undo – displays a set of command options that allow greater control over undoing things. (This is rarely used directly by a user, and is more of a programmer’s tool, so I won’t be going into any detail).
  • Erase – removes from the drawing an object or set of objects as selected by the user.
  • Oops – reverses the last Erase command, even if you have done other things in the meantime. (It also reverses erasures performed by the Wblock command, but such reversal is rarely needed these days).

Note that many commands also have an Undo subcommand  which is different again from all of the above. For example, start the Line command, pick a few points, then enter Undo while still in the command. Just the last segment will be removed, and you can carry on picking more points. Most subcommands can be abbreviated, and this is true of the Undo subcommand within the Line command. While still in the Line command, enter U and this will have the same effect as entering Undo in full (or the other possible abbreviations Un and Und).

This is not the case when entering full command names; entering U and Undo at the command prompt will do different things, although command line auto-complete can confuse matters further depending on your settings. I’ll ignore that for the sake of brevity.

Let’s go through a command sequence that uses all of these things.

  • Enter the Line command (type LINE and hit [Enter]). Pick 6 points to create 5 lines but don’t hit [Enter] yet. While still in the Line command, enter Undo (UNDO [Enter]). This will use the Undo subcommand of Line to undo the last drawn line segment, leaving 4 lines. Pick another 2 points, leaving a total of 6 lines. While still in the Line command, enter U. This will undo the last drawn line segment, leaving 5 lines. Hit [Enter] to finish the Line command.
  • Enter the Line command, pick 4 points to draw 3 lines and hit Enter to finish the command.
  • Enter the U command. The effects of the last command (Line) will be undone, removing all 3 of the lines created by it.
  • Enter the Redo command. The U command is reversed, restoring the 3 lines.
  • Enter the Undo command. This will give you a few options, but the default is the number of steps to undo. Type 2 [Enter] and the last 2 commands will be undone (ignoring the U/Redo), removing the set of 3 lines and the set of 5 lines.
  • Enter the Redo command. The Undo command is reversed, restoring both the 5 lines and the 3 lines.*
  • Enter the Erase command. Select one line from the first group and two from the second, then hit [Enter] to finish the command and those 3 lines go away.
  • Enter the Move command. Select the remaining 2 lines from the first group, hit [Enter] to finish the selection process and pick two points slightly apart to move the lines a short distance.
  • Enter the Oops command. The 3 lines removed by the Erase command are restored, but note that the effects of the Move command are unaffected. If you had used the U command twice to restore the erased lines, the Move command would also have been reversed.

Clear as mud? There are other possible complications depending on various settings, and there are various user interface options for invoking the commands that I haven’t discussed, but this will do to explain the basics.

* The information in this post applies to any AutoCAD from the last 30 years, but as the command set in BricsCAD is almost identical, it can be used for BricsCAD too. Mostly. There is one exception; if you use Undo to perform several undo steps at once, then follow that with a Redo, only one undo step at a time will be reversed. If you want to redo everything, you will need to hold your finger on the Enter key to repeat the Redo command until it runs out of things to redo. Depending on what you want to do, this can either be very handy or rather inconvenient.

Autodesk’s big Cloud failure

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Back in 2011, Autodesk, some other vendors and many industry pundits were utterly convinced of the inevitable and near-imminent victory of Cloud-based CAD over standalone software. I wasn’t. I wanted to get a feel for how isolated my viewpoint was, so I started a poll and let it run for a while. Here’s how that turned out:
 

As you can see, this blog’s readers were less than convinced about the inevitability of that Cloudy future. Not so Carl Bass, who had this to say in an April 2012 TechCrunch interview:

I’d say two to three years from now, every one of our products will be used online. The only way to use them will be online.

 
Here’s what I had to say about that:

So let’s say you’re an AutoCAD user. A successful Cloud push by Autodesk will mean that you and very large numbers of people just like you be using AutoCAD or an equivalent Autodesk product on the Cloud by 2014 or 2015. If that doesn’t happen for you and all the other users of Autodesk products, then that’s failure by definition. Autodesk will have failed to meet its own publicly stated goal, and that’s exactly what I’m expecting to happen …. I am convinced there is a dichotomy between the expectations of Autodesk and those of its customers, and that spells trouble. Autodesk is either going to succeed in pushing its customers into a future they are not expecting, or it is going to fail and be forced to revise its expectations. I predict that the latter will happen…

 
It’s now way past Carl’s predicted online-only timeframe. A successful strategy by Autodesk would mean we Autodesk customers would have all have been exclusively CloudyCADing for a couple of years by now. Is that what happened?
 

Knock me down with a feather, it turns out that Autodesk’s big Cloud-only push has worked out just as predicted, not by Carl but by the readers of this blog. Take a bow, Nostradamuses!

Yes, there are now Cloud-saving options in a lot of Autodesk’s software, as there are in most competitive products. Yes, Autodesk is still attempting (often astonishingly badly) to online-tie-in desktop CAD users. Yes, Autodesk has a lot of Cloud-only software products, even if many of them don’t generate revenue and some of them are headed for the chopping block. Yes, some of Autodesk’s online offerings now have utility. Yes, there are many students and hobbyists out there, often isolated from commercial and production realities, having fun tinkering with Autodesk’s largely free online software and in some cases producing some seriously cool stuff that looks great in Autodesk publicity material.

Real paying customers, using Autodesk Cloud-based products as their primary mission-critical CAD software in a production environment? Not so much. People are still using that terribly old-fashioned desktop software for that. Autodesk has failed to make reality conform with Carl’s prediction.

Why should I care? I care because Autodesk has taken vast sums of money from AutoCAD customers, and is trying hard to extract even larger sums via its compulsory rental scheme. Instead of spending that cash on genuinely useful improvements to the product that is the source of that income and the basis for many of its vertical products generating further income, Autodesk has left AutoCAD to wither on the vine. It has been some years since an AutoCAD upgrade was anywhere near good enough to be worth the amount Autodesk currently charges for maintenance, let alone the trebled(?) amount it likes to think it can get away with charging in a couple of years.

It’s not because there’s no potential for improvement, either. Autodesk gets a lot of feedback about what could be improved in AutoCAD, but ignores most of it, sometimes choosing to do dumb things instead that make things worse. In contrast, Bricsys has proven that it’s possible to make huge strides in improving a straightforward 2D/3D DWG-based desktop CAD application in a single year; Autodesk’s efforts are woefully inadequate in comparison. Meanwhile, by chasing an elusive exclusive Cloudy cornucopia, Autodesk has frittered away a fair fortune on a plethora of production-pointless products.