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AutoCAD

CIRCLES AND LINES: Grips 101

30 Jun, 2004 By: Lynn Allen

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Those little boxes can speed up editing in AutoCAD.

GRIPS REMAIN ONE OF the most powerful editing tools available in AutoCAD (and AutoCAD LT). If you see grips as annoying blue boxes that appear when you least expect them, chances are you don't understand them. With patience, an open mind, and a little help from this article, you'll be on your way to faster, more efficient editing habits. It's been ten years since I last tackled grips, so it's about time to cover them again. Most people barely scratch the surface of their potential.

Grips permit fast and effective editing in the following commands: Move, Copy, Rotate, Stretch, Scale, and Mirror. Grips eliminate tedious steps and as a bonus add some automatic object snaps.

To begin, make sure grips are turned on. Go to the Options dialog box, choose the Selection tab, and click on the Enable Grips box (figure 1). You can also type GRIPS at the Command prompt and set it to 1. You can change the grip color and size in this dialog box as well. I prefer my unselected grips to be blue and my selected, or hot, grips to be red. Blue is a good color for unselected, or cold, grips because it doesn't distract from the drawing objects you select.The size of the grip boxes should be large enough to see easily but not so large they overwhelm-about a quarter of the way across the slider bar is good.

Figure 1. You can set Grips under the Selection tab.

Slow and Easy

To follow along, draw a line, an arc, and a circle. Grips live at the Command prompt and can't be used while a standard AutoCAD command is active. As soon as you enter an AutoCAD command (except for Redraw), all your grips disappear from the screen.

Lines. At the Command prompt, select the line. Three blue boxes appear on your line, one at each endpoint and one at the midpoint.

There are three different types of grips: hot, warm, and cold. When grips are warm, they're ready to be edited. Notice that when you move your cursor within the range of any grip, you're pulled in as though a magnet is at each grip point. Select one of the endpoint grips, and the grip turns red. You guessed it-this is a hot grip. You're now ready to pick the editing mode you need.

The Command line indicates that you are currently in Stretch mode. Notice that as you pull your cursor around, you stretch the line. You can also turn Ortho off for greater flexibility. Press the space bar and Stretch is replaced with Move. As you move your cursor, you're in Move mode. Press <Space> again and you're in Rotate mode. Continue pressing the space bar to try Scale, Mirror, and return to Stretch. Grip mode loops until you select an option. While in Stretch mode, click on your screen where you want the new endpoint. Once you pick a spot, you return to the Command prompt and warm grips.

To make grips disappear, simply press <Esc>. For years we had to press <Esc> twice to clear grips, which is why so many of us veteran AutoCAD users feel the need to repeatedly bang on the poor key!

If you want to mirror something and don't want to page through each option to get there, proceed directly to Mirror by typing MI. Keying in the first two characters of any option takes you to your desired mode. Don't try this unless you've already selected a hot grip. You can also use the right-click shortcut menu to select the mode of your choice (figure 2).

Arcs. Now, pick the arc on your display. While at the Command prompt, pick the edge of the arc to display the three grips. Select the midpoint grip to make it hot. Space through the options to see the different results of each editing selection. Return to the Rotate option. Notice in the Command prompt area that several options are available within the Rotate option:

All editing options have additional selection parameters available. Type c for Copy (or pick Copy from the shortcut menu). Now, as you pick while rotating the arc, you get multiple copies of the arc, much like a polar array. When you've made several copies, press <Enter>, <Esc>, or type x to return to the Command prompt. Only the original arc has warm grips. Press <Esc> again to make the remaining grips disappear.

Circles. At the Command prompt, pick the circle and notice its five grips: one at each quadrant and one in the middle. Make the middle grip hot and page through each option, finishing at the Scale option. You can select or type in a scale factor.

What if you want to move the left grip of the circle to the right endpoint of the line? To edit or move the circle using the grips on the line, the line must have cold grips so it won't move, but the circle needs warm grips. Select the line and the circle so they both have grips. To make the grips on the line cold, hold down the <Shift> key and select the line, but not on a grip. Now the circle is the only object that will be edited.

Pick the grip at nine o'clock on the circle to make it hot. Press <Space> to change to the Move option. Move your cursor until the circle locks into place at the end of the line. The quadrant at nine o'clock on the selected circle falls at the endpoint of the line. All this done with no object snaps!

Make all the grips disappear (press <Esc>) and reselect the circle. Select a grip on one quadrant to make it hot. While in Stretch mode, hold down the <Shift> key while picking a point on the screen. The <Shift> key assumes the Multiple mode (like picking c for copy) and emulates the Offset command.

Hint. When you use the <Shift> key with any of the grip editing commands, you are in Multiple mode.

Other Grips

Grips appear at different points on different objects. Because a polyline is one continuous object, the grips appear at each vertex. Stretching the individual vertices of a polyline is much easier with grips than with any of the standard AutoCAD commands. Grips leave the Pedit command in the dust.

Create a vertical dimension and select it to display its grips. The grip you select as the hot grip makes all the difference in the world with dimension objects. If you select one of the dimension line grips, you can move only the dimension line location. Picking an extension line grip lets you relocate the selected extension line, which also modifies the dimension value. If you want to move the dimension text, pick the grip on the text and move it to the desired location. Editing dimensions with grips is very flexible and efficient.

Figure 2. The right-click menu for Grips.

Returning to the Options dialog box, pick the checkbox labeled Enable Grips within Blocks. Insert a block and display its grips. Many grips appear, and you can use any of them as your hot grip. Don't be fooled into thinking that you can edit the individual objects of the block without exploding it. Grips don't let you break any standard AutoCAD rule. I suggest that you return to the Grips dialog box and turn this feature off-all those grips get very confusing!

Sometimes the hot grip is not where you want the base point for the object you're editing. All the grip editing modes provide the additional option of base point as a selection. For example, if I want to mirror a library symbol, Grip mode assumes I want to mirror around the hot grip. Instead, I can use the base point option to change the first point of the mirror axis to suit my needs.

You can also stretch more than one hot grip at a time. For example, sometimes you need to stretch two or more different grips with the same Stretch. Just hold the <Shift> key down while you select grips and you can select more than one hot grip (figure 3). This is a great way to quickly extend the length of a rectangle.

Ode to Shift

The magical <Shift> key provides four distinct functions:

• 1. places you into Multiple mode while editing (same as copy),
• 2. repeats the last distance or angle while editing,
• 3. lets you select more than one hot grip for stretching, and
• 4. turns warm objects cold.

One More Grip Tip

Grips are smart enough to remember and repeat preselected angles, distances, and scale factors. Return to the line you've already drawn and display the grips. Make the midpoint grip hot and go to Rotate. Pick the Copy option-notice the Command prompt indicates **COPY (multiple)**. We're going to explicitly key in 20 for a 20° rotation angle. Our magical shift key comes into play one more time. Hold down <Shift> and move the cursor around the two lines. You'll notice an auxiliary snap occurring at 20° increments. Select while you hold down <Shift>, and you make evenly spaced copies of the line as you move around in a circular fashion.

Figure 3. Hold down <Shift> while you select grips to pick more than one.

The <Shift> key also remembers distances when copying or mirroring. Say you need five copies of a desk block, each eight feet apart. Select the desk, make a hot grip, and use the Move and Copy options to input the first distance of @8'<90 (eight feet up at an angle of 90°). After the original distance is set, use the shift key to copy the remaining desks into place-all at eight-foot increments (much like a rectangular Array).

Undos and Other Warnings

All grip editing functions provide an Undo option to undo the effects of the last step. An Undo at the Command prompt undoes all the editing that took place in the last grip mode, so be careful. Remember that you didn't execute a standard AutoCAD command at the prompt to get into grips.

Pressing <Enter> at the Command prompt won't get you back into grip mode. This action repeats the last standard AutoCAD command instead of entering grip mode. Most likely, all of your grips will disappear. The only way to enter grip editing mode is to select a hot grip.

Highlighted objects with warm grips are also fair game for use within other AutoCAD commands. If immediately after some grip editing you go into the Erase command, AutoCAD assumes you want to erase the highlighted objects you just worked so hard on. Always clear your grips by pressing the <Esc> key before you enter a standard editing command.

Experiment

Recent releases of AutoCAD added the ability to turn on grip tips-I dare you to say that three times fast. This sounds like some great new feature to guide you through the use of grips, but in reality it's reserved for tips that come with custom objects. Because standard AutoCAD doesn't come with any custom objects now, we won't get too excited about it just yet. You can also control the maximum number of objects AutoCAD displays with grips if you find yourself becoming a bit grip-ophobic!

Experiment with grips-force yourself to use them. Even if you don't want to be a grip expert, there's no effort required to quickly move blocks and text objects around on your drawings using the simplest of grip fundamentals. AutoCAD provides many roads to the same end-some faster than others. Using grips is just another road along the route of efficient editing. Until next month-happy AutoCAD-ing!

Lynn Allen is the AutoCAD technical evangelist for Autodesk in San Rafael, California, and the author of AutoCAD 2002: Inside and Out from CMP Books. E-mail her at lynn.allen@autodesk.com