LT Unlimited

New Tab for Array Creation

When Associative Arrays were introduced in AutoCAD LT 2012, they had a great contextual ribbon tab that showed up when you selected a completed array…but didn’t have one during creation. There were still command-line options, of course, but sometimes it’s nicer to see all the options. So this year, we added an Array Creation tab to AutoCAD LT 2013.

Here’s the one for rectangular arrays:

There are variations for path & polar arrays too. You’ll notice that they contain pretty much the same items as the Array editing tab—really the only difference is that the Edit tab adds a panel with the Edit Source/Replace Item/Reset Array commands.

Another tweak to the Array command you’ll notice is that, for rectangular and polar arrays, AutoCAD LT now automatically places the objects for you, as a sort of preview.

For rectangular arrays, you get 3 rows and 4 columns:

And for polar arrays, you get 6 items evenly spaced around the full 360 degrees:

These objects are placed as soon as you finish selecting the object (for rectangular arrays) or as soon as you specify the center point (for polar arrays).

And of course, you can change the count and spacing right away—with the grips, dynamic input, or the new ribbon tab—or after, again using grips/ribbons/etc.

There’s been a neat upgrade to path arrays too, but it’s a little tricky to explain (it’s not hard not to understand, just to describe in words), so I’ll save that for next time.

Drawing Donuts

Drawing donuts in AutoCAD LT might not be as fun as doing donuts in a parking lot, but it’s a lot easier. (Unless your parking lot is covered in ice as they often are in the winter…then AutoCAD donuts are just safer.) And they might not taste as good as the once you get from the corner bakery, but they won’t leave powdered sugar on your drawings either.

You’ll find the Donut command on the expanded portion of the Draw tab.

What is a donut? Just a closed polyline, usually with a non-zero width, consisting of two arcs joined end to end.

You define a donut by first entering its inside diameter, then the outside.

Once you’ve plugged in those numbers, you can click to create as many donuts as you like before exiting the command.

If you select one of your newly created donuts and check out its properties, you’ll see that the width is equal to your outside diameter minus the inside diameter divided by 2 (W = (OD-ID)/2), and the radius of the arc is equal to the half the inside diameter plus half the width (R = (ID+W)/2). That’s because polylines are defined by their centerlines, not their edges, so AutoCAD LT has to do some math behind the scenes to generate the donut.

You can use the Donut command to generate closed filled circles, too – just enter 0 for the inside diameter.

On the right are some donuts of varying sizes (although sadly, none are custard-filled).

Create Freehand Sketches

One of the new-to-AutoCAD-LT commands in AutoCAD LT 2011 is the Sketch command. Previously available only in AutoCAD, Sketch received a makeover in this release (in both AutoCAD and LT) and is now easier to use and more flexible.

By default, Sketch is only available from the command line, but you can create a button for it if you want. Once you start it, left-click to start a sketch, then – without clicking – drag the cursor along the path that you want. Left-click again to end that sketch path, and left-click once more to start a new path. When you’re finished, press Enter to record the sketch.

The green color you see while the command is active has nothing to do with the current layer or color – all sketches are green while they’re being created.

Within the Sketch command, you have three options for controlling a sketch’s appearance and behavior: Type, Increment, and Tolerance.

Type controls what kind of objects are created when you finish the sketch. Your choices are Lines, Polylines, and Splines. (Unless you really want a headache or two, don’t choose lines.)

Increment determines the size of individual sketch segments for polylines and lines, or how far you have to move your mouse before a new segment is drawn. Smaller numbers mean smoother sketches, bigger increments lead to rougher sketches. What increment you choose will depend on the scale of your drawing and the purpose of the sketch.

Tolerance is only relevant if you’ve chosen Spline as your object type. It controls how close the finished sketch comes to the points your cursor passed through. Tolerance can be set to any value between 0 and 1 (inclusive), where 0 means the spline fits perfectly to the mouse path (potentially a very rough line) and 1 provides the smoothest curves (potentially not very close to where your mouse went). The default value is 0.5, and you can experiment to see which value works best for your sketches.

In the image below, the sketch on the left had a tolerance of 0.5, the one in the middle had a tolerance of 0, and the one on the right had a tolerance of 1.

Match Hatch Properties

The ability to set the properties of a new hatch to match those of an existing one has been around for a long time. Before 2011, this tool was called “inherit properties” and it was limited to hatch-specific properties like pattern, angle, and scale.

AutoCAD LT 2010 hatch preview, before “inherit properties” (current layer color is white, existing hatch layer color is red):

AutoCAD LT 2010 hatch preview, after “inherit properties”:

In AutoCAD LT 2011, this feature has been renamed to “Match Properties” because it behaves much more like the regular “Match Properties” command. Now, whether you’re creating or editing a hatch, you can match ALL the properties of another hatch, including color, background color, and layer. You can even choose whether you want to use the current value for the new hatch’s origin or use the origin of the hatch you’re matching.

AutoCAD LT 2011 hatch preview, before “match properties” (current layer color is white, existing hatch layer color is red, hatch layer is set to “use current”):

 

AutoCAD LT 2010 hatch preview, after “match properties”:

Updates to the Spline Command

The new 3D modeling tools in AutoCAD 2011 required some updates to the spline command, and while a lot of them are most applicable to 3D situations, some of them have trickled over to the 2D side.

You’ll notice the first change right after you start the command, if you pay attention to the options at the dynamic prompt or command line.

“Object” has been around for a while (it turns a polyline into a spline), but “Method” and “Knots” are new to AutoCAD LT 2011.

“Method” lets you choose between “Fit Points” and “Control Vertices.” Fit Points is the old familiar way, where the spline passes through each point that you select. With Control Vertices (CV), you essentially define bounding lines and the spline fits between them. (That’s an overly simplistic explanation, but let’s just say that CV splines are important for 3D modeling, and you should go check out Guillermo Melantoni’s What A Mesh blog if you want to know more.)

Here are examples of the two methods, first with fit points, then with CV.

Whichever method you choose, you can change the display later.

Knots affect the shape of a fit spline as it passes through fit points. There are 3 options (Chord, Square Root, and Uniform), but I’m honestly not sure how to explain the differences.

Maybe the biggest change you’ll notice is that when drawing a fit spline, the start and end tangencies are now assumed. You can change it with the Tangency options if you want to, but you don’t have to. (Admit it – when you finish a pre-2011 spline, you just hit Enter-Enter-Enter anyway, right?)

Splines also have some new fancy grips, and they’re multifunctional like the ones for polylines and hatches.

The options you’ll see are a little different depending on whether you’re working with a fit spline or a CV one, but the concept is the same.

In the image above, the triangular grip is for switching between Fit and CV display. The “plus” on the left-hand grip indicates the beginning of the spline (to help identify “start” and “end”). For the square grips, you can stretch, add, and remove fit points, and for the start/end grips you can change the tangent direction.

Transparency for Objects and Layers

Another major AUGI wish granted in AutoCAD LT 2011 is transparent objects and layers.

In the image below, first the solid hatches are on top of the main geometry (obviously not ideal), then sent to the back of the draw order (still not optimal), and finally made transparent, so that the important objects can be easily seen.

Transparency works just like other object properties like color and linetype. You can set it globally or per viewport in the Layer Properties Manger:

Or you can set it per object from the Properties palette or the Properties panel on the Home tab.

 

The most obvious application is for hatches, to highlight areas without obscuring other geometry, but you could also fade an entire layer, perhaps to indicate a demo or existing condition, or a raster image, so that what you draw on top of it stands out more clearly.

One thing to remember about transparency is that, by default, it is turned OFF for plotting. This is because transparent objects need to be rasterized for printing, and this can slow plotting down in certain situations. To turn transparent plotting on, check the box in the expanded portion of the Plot dialog.

Hatch Improvements in AutoCAD LT 2011, Part 1

There have been some major changes and improvements in hatch creation and editing in AutoCAD LT 2011. Some of them are easy to spot, but some of them you have to look for. Today’s post will focus on the creation side of hatches, and the next will be about editing.

When you fire up the Hatch command in AutoCAD LT 2011, you’ll notice that something is missing: the dialog box.

Instead, a contextual tab appears with all the options previously available in the dialog, plus a few more. (Click on the image to see it full-size.)

You can set the boundary detection method, pattern, angle, scale, origin, and more directly from the tab.

If you’re using the “pick points” method, hovering over an eligible area shows you an instant preview of what the hatch will look like, so you can adjust your properties as needed.

After you click, the hatch becomes immediately visible.

As you continue clicking to select areas, keep in mind that even though it *looks* as though separate hatch objects are created with each click, the final result will still be a single object unless you have “Create separate hatches” turned on under the Options panel.

Amid all these familiar hatch settings are two new options: Background Color, and Layer. They’re both on the Properties panel, but Layer is in the expanded portion.

Background color enables you to have a line pattern AND a fill color in the same hatch object, creating the effect of layering hatches. It can be set to any color you like except By Layer.

With the Layer property, you can set the default creation layer for new hatch objects. That way, no matter what the current layer is, hatches will always be created on the same layer.

This setting is persistent within a drawing, so if you set the hatch layer in your template file, you’ll never have to set it again. Now, is that a time-saver or what?

Tune in next time for hatch editing improvements!

One more reason to leave Dynamic Input on

Last week, I put up a post about why you shouldn’t be in a hurry to turn dynamic input off if coordinate entry isn’t working the way you expect it to.

I left one part out, though – relative vs. absolute coordinates.

By default, dynamic input uses the “relative” method of coordinate input. It assumes that you’re entering deltas instead of actual coordinates. If you start a rectangle at 6,3 and want it to be 8 units wide and 4 high, you’d enter 8,4.

But sometimes, you want to use absolute coordinates instead. Then the second point of that rectangle above would be 14,7.

If this is a once-in-a-while situation, just preface your coordinate entry with the # sign to temporarily use absolute coordinates.

But if it’s your primary workflow, DON’T just turn off dynamic input! Instead, read this post to see how you can change the input settings to whatever fits you best.

Remember, this is AutoCAD LT…there’s almost always a way to make it work the way you work.

Don’t touch that button!

My apologies for the melodramatic post title, but there’s a Dynamic Input issue in the discussion groups that I’d like to see go away. Whenever someone complains that numeric entry isn’t behaving the way they expect it to, the first suggestion is always “Turn Dynamic Input off.” But this is AutoCAD! There’s almost always a way to get it to adapt to your workflow! You don’t have to turn features off! At least, not before you understand all your options, so you’re at least making an informed decision.

I’ve covered all the settings of Dynamic Input in two previous posts (Part 1 and Part 2), but the setting that probably generates the most questions is DYNMODE, or Pointer and Dimension Input.

When Pointer Input is turned on (DYNMODE = 1), you get a mini command line next to the cursor, where you see what you type, whether there’s a command active or a grip selected or not.

If Dimension Input is turned on (DYNMODE = 2), you don’t get the preview next to the cursor anymore. Instead, you get dimensions next to a selected object (showing length, angle, change in length or angle, etc.) where you can enter new values to change the size of the object. You can also press TAB to cycle through the available dimension fields. In the first image below, the active field is “change in length,” and the second is “total length.”

You can also turn them both on, by checking both boxes in the Dynamic Input settings dialog, or by setting DYNMODE to 3. In that case, you get dimension input when it’s available and pointer input when it’s not.

Dimension input is usually the source of the complaints, mainly because you can’t use it to enter the change in value of a block parameter, only the total value. If that bothers you, though, just turn the dimension part of the input off – don’t scrap pointer input until you’re really sure you don’t want it. Personally, there have been times when I’ve turned dimension input off, but I’d hate to have to draft without the heads-up display of the pointer input.

Maintain Readability for Linetypes with Text

In AutoCAD LT 2010, there was a handy little feature called “reverse” that helped you manage linetypes with text in them. Reverse enabled you to swap the endpoints of a line, thereby flipping the text as well. (If you need a refresher, click here.)

The trouble with Reverse, though, is that it didn’t help with circles, or with polylines that doubled back on themselves.

In AutoCAD LT 2011, that loophole has been closed. Now, text in linetypes is always readable, regardless of the line’s orientation.

 

(Okay, so a closed circular gas line isn’t very practical. But at least now you can read it all the way around!)

All the linetypes that ship with AutoCAD LT 2011 have been updated to behave this way, but if you have your own custom linetypes that you’re bringing forward you’ll want to modify the rotation parameter in the linetype definition from R (for “relative") to U (for “upright”).

Old way:
*GAS_LINE,Gas line ----GAS----GAS----GAS----
A,.5,-.2,["GAS",STANDARD,S=.1,R=0.0,X=-0.1,Y=-.05],-.25

New way:
*GAS_LINE,Gas line ----GAS----GAS----GAS----
A,.5,-.2,["GAS",STANDARD,S=.1,U=0.0,X=-0.1,Y=-.05],-.25