Object snap tracking tracks the coordinates on object snaps and for this task, you need to track the midpoint of the rectangle’s sides. Here are the steps:

In an earlier post, Ellen showed how to align a rectangle with a line on the fly. You can easily create the same effect using AutoLISP. This AutoLISP routine is simple, and you [...]]]>

This is a guest post by Sanjay Kulkarni, an AutoCAD programmer. You can read more about him at the end of this post.

In an earlier post, Ellen showed how to align a rectangle with a line on the fly. You can easily create the same effect using AutoLISP. This AutoLISP routine is simple, and you can use the code as a starting point for your own routines.

First, Ellen has created a video to show you how this works.

Here are the steps to use this AutoLISP routine:

1. Download the AutoLISP file. You need to do this only once, of course.
2. Start the APPLOAD command. In AutoCAD 2012, you can go to Manage tab>Applications panel>Load Application.
3. In the Load/Unload Application dialog box, make sure that the Files of Type drop-down list displays the .lsp extension. In the Look In box, navigate to the AutoLISP file and select it.
4. Click the Load button. You should see a message at the bottom of the dialog box saying that the file was successfully loaded.
5. Click Close to close the dialog box. For a quicker method of loading a program, see my tip, “Loading AutoLISP programs quickly“.
6. Draw a diagonal line in your drawing.
7. On the command line, type ra and press Enter.
8. Follow the prompts. At the Select the line to align rectangle with: prompt, select the line to align the rectangle with. The program repeats the prompt until you select a line or press the Escape key to abort the program.
9. At the Specify first corner point or [Chamfer/Elevation/Fillet/Thickness/Width]: prompt, specify the first corner of the rectangle. You can now see that the rectangle is aligned with the line.
10. At the Specify other corner point or [Area/Dimensions/Rotation]: prompt, specify the other corner of the rectangle to finish the routine and create a rectangle aligned with the selected line.
    

Tip: You can repeat the command in the drawing as long as the drawing is open. But if you open another drawing you will need to reload the program. To avoid having to do this, you can add it to your Startup Suite. In the Load/Unload Application dialog box, drag the AutoLISP file from the list of files at the top to the Startup Suite in the lower-right section of the dialog box.

I won’t show you the actual code in all my posts, but this one is simple enough that it will be useful to look at its structure. As I said, you can use this same structure for many situations. It’s similar to a script file; you are using the COMMAND function to execute an AutoCAD command. The code also defines an alias, RA. The PAUSE function waits for your input. Of course, the code also defines some variables, does some error checking, sets up the prompts, and a little more.

(defun RectAlin ()
(setq oOSMODE (getvar “osmode”))
(setvar “osmode” 0)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; selecting the line
(setq theLine nil)
(while (= theLine nil)
(setq theLine
(car
(entsel
“\nSelect the line to align rectangle with [Escape to cancel]:”
)
)
)
(setq eLstLine (entget theLine))
(if (/= (cdr (assoc 0 eLstLine)) “LINE”)
(setq theLine nil)
)
)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(setq sPt (cdr (assoc 10 eLstLine)))
(setq ePt (cdr (assoc 11 eLstLine)))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Create aligned rectangle
(command “rectang” PAUSE “R” “P” sPt ePt PAUSE)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(setvar “osmode” oOSMODE)
(princ)
)
(defun c:RA ()
(RectAlin)
)

Do you use AutoLISP in this way? Let us know how you use simple routines like this in your work–leave a comment!

Sanjay Kulkarni is an experienced CAD (AutoCAD, Inventor, SolidEdge, CATIA, NX) programmer and a member of the Autodesk Developer Network. He is fluent in AutoLISP, VBA, and VB.NET. He has written for AugiWORLD and Inside AutoCAD (a monthly magazine that has since gone out of publication). He can be contacted at sanganakskha@gmail.com

Here are the steps:

Thanks to Joel, whose comment to the earlier post helped [...]]]>

In a previous post, “Create a rectangle with a flexible corner,” I showed how to create a rectangle whose upper-right corner is strechable, creating a flexible rectangle that doesn’t lose its shape. In this post, I show how to do the same with a dynamic block.

Thanks to Joel, whose comment to the earlier post helped me figure this out.

When you grip-edit the upper-right corner of a viewport to stretch it, the viewport keeps its rectangular shape. You can freely choose your new corner location, so you’re not just scaling. You can change the proportion between the width and height, all without [...]]]>

Have you noticed how grip-editing a viewport is different from grip-editing a rectangle?

When you grip-edit the upper-right corner of a viewport to stretch it, the viewport keeps its rectangular shape. You can freely choose your new corner location, so you’re not just scaling. You can change the proportion between the width and height, all without losing its rectangle-ness.

Stretching a viewport

But when you grip-edit the upper-right corner of a rectangle, the rectangle is distorted. The rectangle doesn’t know that it’s supposed to remain a rectangle. AutoCAD just thinks of it as a 4-sided, closed polyline. Indeed, select it and check in the Properties palette (Ctrl+1) and you’ll discover that it is indeed just a polyline.

Stretching a rectangle in AutoCAD

AutoCAD 2010′s geometric parameters can help you easily create a rectangle that knows it’s a rectangle. And, what is a rectangle? Well, “rect” means right, as in 90°. “Angle” is self-explanatory. So, we need to ensure that the angles will stay 90°.

Here’s how:

1. Draw a rectangle.
2. Go to Parametric tab> Geometric panel, and click the Perpendicular button.
3. At the Select first object: prompt, click the top horizontal line of the rectangle.
4. At the Select second object: prompt, click the left vertical line. You’ll see the Perpendicular icon near the upper-left corner of the rectangle.
5. Repeat the process for the two lines that meet at the lower-left corner and the lower-right corner.

A rectangle with 3 perpendicular geometric constraints

Note: If you try to do all 4 corners, you’ll get a message telling you that AutoCAD can’t apply the constraint. That’s because when you have 3 corners constrained to perpendicular, the last corner is superfluous, and is therefore an overconstraint.

You can't overconstrain an object in AutoCAD

Now, you can grip-edit that upper-right corner and it will behave just like a viewport!

The rectangle now stretches like a viewport!

Here’s a video of the same operation:

In this tutorial, you create an architectural dimension style. Why? Because the default style is a mechanical look and by changing it to architectural, you’ll get [...]]]>

Are you getting the look you need for your dimensions? Are you constantly making little adjustments? If dimensions aren’t your friend, you need to get more comfortable with dimension styles.

In this tutorial, you create an architectural dimension style. Why? Because the default style is a mechanical look and by changing it to architectural, you’ll get a chance to work with many of the dimension style features.

Note: The values that I chose in this tutorial are my choices. They don’t come from any standard; you should follow the standards in your office or discipline.

Follow these steps:

Open any architectural drawing. If you don’t have one, open a new drawing and choose Format > Units. Change the units to architectural. Draw a rectangle 40′ wide by 30′ high and zoom to its extents. Zoom out a little more so you have room for your dimensions.

If you’re starting with a new drawing, create a new layer, named dim and make it a different color from your rectangle. Set it current. Make sure that OSNAP is on with a running object snap for endpoints.

Choose Dimension > Dimension Style or click Dimension Style on the Dimension toolbar to open the Dimension Style Manager.

Click New. In the Create New Dimension Style dialog box, enter arch_96 and click Continue. The 96 refers to the scale that we’ll use later.

Note: We won’t use it now, but click the Use For drop-down list. You can see that you can create a style that applies only to a certain type of dimension. For example, you may want angular dimensions to have open arrows but the rest of your dimensions to use architectural ticks. So you could create a dimension style just for angular dimensions.

Click Continue.

The New Dimension Style: arch_96 dialog box opens. Click the Lines tab.

Note: In the Dimension Lines section, you can make the dimension line’s color, linetype, and ineweight different from the rest of the dimension. We’ll leave it the same, which is more typical.

Note that the Extend Beyond Ticks box is grayed out. That’s because you don’t have architectural ticks (and I hope you don’t have any other kind either). To create the ticks, click the Symbols and Arrows tab. In the Arrowheads section, choose Architectural tick from the First drop-down list. The Second drop-down list follows suit automatically. Choose Open from the Leader drop-down list. The arrow size should be 3/16″.

Click the Lines tab again. Set the Extend Beyond Ticks value to 1/16″.

Leave the Baseline Spacing value at 3/8″. This is the spacing between the dimension lines of two baseline dimensions.

Note: You can suppress the first or second dimension line. These are the lines to the left or right of the text. As you’ll see later, architectural dimensions only have one dimension line, so this doesn’t apply to us.

In the Extension Lines section, you can change the color, linetype, and lineweight of the extension lines. We’ll leave them unchanged.

Note: You can also suppress the first or second extension line. Normally, you would do this only for a special situation where an extension line doesn’t fit well. You would create an override to a dimension style for this purpose. (That’s for another tip!)

Change the Extend Beyond Dim Lines value to 1/8″. This is the amount that the extension lines extend beyond the dimension lines.

Change the Offset from Origin value to 1/8″. This is the distance from the object you’re dimensions to the extension line.

Click the Symbols and Arrows tab, just to see what’s there. (Before Release 2006, you’ll have one tab called Lines and Arrows.) You’ve already change the arrowhead. The rest of this tab is for center marks, arcs, and radial dimensions, which don’t concern us, so click the Text tab.

The first step is to choose a text style. If you don’t already have one, you can create it now. Click the Ellipsis button to the right of the Text Style drop-down list.

In the Text Style dialog box, click New. Name the style dimtext_96 and click OK.

In the Text Style dialog box, choose a font from the Font Name drop-down list. Architects like a font that looks hand-drawn. I chose Stylus BT. If you don’t have that on your system, choose another one. The important point is to keep the Height at 0′-0″ because that allows the height in the dimension style to take precedence. Click Apply and click Close.

Back in the New Dimension Style: arch_96 dialog box, choose dimtext_96 from the Text Style drop-down list. You can change the color of the text and also place a fill box around the text (for legibility over other objects), but we’ll leave these the same. The text height should be 3/16″. Note that the Fraction Height Scale text box is grayed out. We’ll come back to that later.

In the Text Placement section, choose Above from the Vertical drop-down list.

In the Text Alignment section, choose Aligned with Dimension Line. Notice how the preview changes dramatically and starts to look like an architectural dimension.

Click the Fit tab. This tab specifies how lines and arrows fit, especially if there isn’t enough room. You also set the scale here.

In the Text Placement section, choose Over Dimension Line, with Leader.

In the Fine Tuning section, check the Draw Dim Line Between Ext Lines so that even if the text can’t fit between the extension lines, there’s still a dimension line.

In the Scale for Dimensions section, change the scale to 96. Of course, this value depends on the size of your model and the size of the paper you’ll be using. You would use the Scale Dimension to Layout option for dimensioning in paper space on a layout. See my tip Dimension in paper space.

Click the Primary Units tab. From the Unit Format drop-down list, choose Architectural. Leave the precision as 1/16″.

From the Fraction Format drop-down list, choose Diagonal.

In the Zero Suppression section, uncheck the 0 Inches check box to show 0 inches.

Now click the Text tab and change the Fraction Height Scale value to .75. (You can’t do this until you’ve specified a unit format that uses fractions.

If you want to include alternate units, such as metric (if you’re main units are Imperial), use the Alternate Units tab.

Click OK.

In the Dimension Style Manager, with arch_96 selected, click Set Current and click Close. You’re now ready to dimension.

Choose Dimension > Linear or click Linear on the Dimension toolbar. Press Enter so you can select an object. Pick any side of the rectangle (or any object in your pre-existing drawing, if you opened one). Specify a location for the dimension line, leaving room for the text.

Happy dimensioning!

But others are more elusive.

For example, recently someone asked me, “I would like to ask if there is a simple way to select a center of a rectangle.”

My answer was: If you press Shift [...]]]>

Some coordinates are easy to find. For example, to find the endpoint of a line, you just use the Endpoint object snap.

But others are more elusive.

For example, recently someone asked me, “I would like to ask if there is a simple way to select a center of a rectangle.”

My answer was: If you press Shift and right-click, you’ll get the OSNAP menu. Choose Mid Between 2 Points, and choose two diagonal corners.

Finding coordinates is a very common task, so here are some other tips for specifying hard-to-find coordinates.

Polar coordinates

To find a point at a specific angle, use polar coordinates, in the format distance<angle. So, to draw a line that is 3.5 units at a 15°, enter 3.5<15.

Apparent Intersection OSNAP

The Apparent Intersection object snap finds an intersection that would be created if you extended two objects until they met. It’s very simple to use. You start a command, such as the LINE command, specify the OSNAP (you can type app), specify a first point, such as an Endpoint, then hover over the second point. You’ll see an X at the apparent intersection. Just click to lock in the coordinate.

Watch the video.

Extension OSNAP

The Extension object snap extends lines and arcs in the same direction, past their endpoints. Look for the Extension tooltip; at the same time you’ll see a temporary extension path.

Watch the video.

Object snap tracking

Object snap tracking lets you specify a point based on object snaps of existing objects. When you’re looking for the intersection of two existing endpoints, it works similarly to the Apparent Intersection OSNAP. But it has more uses that that. For example:

• Your want the endpoint of a line you’re drawing to be vertical to the endpoint of an existing line.
• You want to center a circle inside a rectangle
• You want to start a line where two existing lines would intersect if they extended (you can do this with the Apparent Intersection object snap, too)

Note that you can use object snap tracking with polar snapping, so the angles don’t have to be orthogonal.

Follow these steps:

1. Turn on at least one running object snap. To do so, right-click the Object Snap (OSNAP) button on the status bar and choose an object snap, or choose Settings first (depending on your version).
2. Click the Object Snap Tracking button on the status bar (which is different from the Object Snap button). to turn on this feature.
3. Start a drawing command that requires you to specify a point.
4. Hover the cursor over an object snap, to acquire that point. You see a small plus sign at the object snap point.
5. If necessary, acquire a second point.
6. Move the cursor toward the coordinate you want to locate until you see one or two temporary, dotted alignment paths. You’ll also see one or two tooltips and an X.
7. Click to specify the point. Then continue the command you started..

Here, I started the CIRCLE command and acquired the midpoints of the two sides of the rectangle to find its center. This specifies the center of the circle at the center of the rectangle.

Here’s the result:

Temporary tracking

You can also use temporary tracking to accomplish the same result, as long as the angles are orthogonal. Follow these steps:

1. Turn on at least one running object snap. To do so, right-click the Object Snap (OSNAP) button on the status bar and choose an object snap, or choose Settings first (depending on your version).
2. Start a drawing command that requires you to specify a point.
3. Type tk and press Enter.
4. At the First Tracking point: prompt, specify an object snap by clicking it. It must be horizontal or vertical to the final point that you want to specify.
5. Move the cursor horizontally or vertically toward the desired coordinate. You see a solid, temporary rubber-band line.
6. At the Next point: prompt, move the cursor from the rubber-band line to the second object snap, and click.
7. Press Enter to end tracking and continue the command.

Point filters

Point filters are the original way to specify coordinates that aren’t on an object, based on object snaps of existing objects. Most people use object snap tracking now, but they can still be useful, especially in 3D work. You build an X,Y (or X,Y,Z) coordinate by using the X coordinate of one object snap, the Y of another, and perhaps a Z of another.

Follow these steps:

1. Start a drawing command that requires you to specify a point.
2. Type .x or .y and press Enter. (You can also Shift + right-click to choose a point filter from the object snap menu.) Let’s say I start by typing .x.
3. At the of (need YZ): prompt, use an object snap to specify the x coordinate of the desired coordinate. To continue the example of drawing a circle centered inside a rectangle, you would specify the midpoint one of the rectangle’s horizontal lines, because the x coordinate of the circle’s center should be the same as the x coordinate of the horizontal line’s midpoint.
4. Now, simply specify the object snap on an object to locate the y coordinate. In this example, specify the midpoint of one of the rectangle’s vertical lines.
5. AutoCAD locates the coordinate and you can continue the command.

From

From is a feature that lets you find coordinates off objects by specify the offset from an object snap. You can specify that offset as the x,y distance or polar coordinate notation.

Follow these steps:

1. Start a drawing command that requires you to specify a point.
2. Type from and press Enter. (You can also Shift + right-click and click From on the object snap menu.)
3. At the Base point: prompt, specify the base point with an object snap.
4. At the Offset: prompt, enter @ and relative x,y or polar coordinates. Note: You must use @ even if you are using a default of relative coordinates.
5. Continue the command.

Do you have other ways of locating hard-to-find coordinates?

To add thickness, select the object and open the Properties palette. Choose the Thickness property and change the number in the [...]]]>

You can create 3D objects by adding a thickness to them. These objects function like 3D surfaces. For example, you can create a cylinder from a circle or a box from a rectangle.

To add thickness, select the object and open the Properties palette. Choose the Thickness property and change the number in the Thickness text box. Press Enter.

Funnily enough, when you create objects using thickness, only objects that you drew starting with a circle, a wide polyline, or using the SOLID command (which is a 2D command, just to confuse you), have tops. If you start with a rectangle or polygon, you don’t get a top.

You can’t see the difference until you use the HIDE command or shade the objects. Here you see some 3D objects before hiding.

Here you see the same objects after hiding. The one that I created from a rectangle doesn’t have a top (or a bottom).

If you need a box that has a top or bottom, you have several choices:

• Use a wide polyline and add thickness
• Use the BOX command on the Solids toolbar to create a true solid
• Use the _AI_BOX command on the Surfaces toolbar (the button’s tooltip just says “Box”) to create a true surface
• Use the SOLID command and add thickness