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Part 3

OBJECT SNAP AND MODIFY TOOLS

Object Snap. We will now see a very useful feature of Autocad: "object snap" , this utility allows us to draw accurately and faster.

Suppose you have drawn a line and now you will want to do another one, that starts exactly at one end, or in the middle of the line already done.

It appears, therefore, the need to "attach" the second line to the existing first, but how do we combine it with precision?

If we go to the eye may appear to work and the two lines are joined, but doing a zoom closer to the point of union will be that it is not so, even if only

slightly.

We must ensure however that the lines are perfectly combined in the desired location.

To do this we must serve the "Object Snap" that are nothing but a kind of magnet that allows us to interact with various objects in the drawing of their

second set of points, such as the end or the center of an object, highlighting these issues with special symbols that appear at the time of their

intervention at the point concerned the design.

The "snap" has its own special toolbar that can be made visible or invisible by clicking the right mouse button on any of the existing toolbar and

selecting the "Object Snap" in the menu that appears.

Here it is:

Each key corresponds to a different function, we see the main

= Endpoint . Corresponds to the ends of lines or arcs and angles of geometric figures.

When activated on the screen a yellow square on the end checked.

= Midpoint . Corresponds to the midpoint of a line, arc, or one side of a geometric figure.

Its activation appears a yellow triangle at the point selected.

= Intersection. Corresponds to the point of intersection between two lines.

Its activation appears similar to a cross "X" at the point selected.

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= Center. Corresponds to the center of a circle, an arc or an ellipse.

A circle to its activation appears

= Quadrant. Corresponds to the end of the circle, an ellipse or an arc, compared to the X and Y axes UCS.

Its activation appears a small yellow diamond.

= Tangent . Corresponds to the tangent on a circle, an ellipse or an arc, compared to the point where you take a line.

Its activation appears a circle with a dash above.

= Node . The node corresponds to a point that can be drawn (we have not seen it yet) or even the definition points of dimensions (these are also to

be seen) and the center of the text of the same.

Its activation appears a circle with a cross in the center.

= Perpendicular . Corresponds to the perpendicular to an object from the point from which you take a line.

It allows us to bring a line perpendicular to another, even without going to meet her.

The symbol that distinguishes it is when you turn a corner with a square inside.

= Nearest. With this command you can select any point on an object. Its activation symbol appears like an hourglass.

= Snap to None. Clicking on this will temporarily disable all snap, useful when working with ' AutoSnap active, and soon we shall see.

Well the use of object snap is very simple, and takes place within the various commands of AutoCAD.

For example, after activating the command line, before selecting the first point of this, you can click on the snap "midpoint" and then establish the

first point of the line to be built exactly on the midpoint of another, then you can still select another snap, such as "endpoint" and then go to select

the second point of the line at one end to another.

So for the other object snap according to their related functions.

You have to do some tests with the snap, then we will see one more important benefit you will facilitate a lot of snap in their use, it 's AutoSnap.

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Osnap Settings.

By clicking on the last snap of the toolbar button, opens the following window:

By checking the first check box in the upper left corner where it says “Object snap on (F3)”, you enable or disable the AutoSnap.

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As you see for each item of the object snap, is show on the left the symbol that appears on the screen when it is activated and you need to precisely

identify the various types.

Check the box to those that you use mostly during the design, in this way they will be activate automatically on joining point.

Set them as shown, and then click OK.

At this point the AutoSnap is set and active, which means that when we use any drawing tool that requires you to establish points on the screen, every

time you approach the cursor to a point that AutoCAD will recognize as being equal to one set of snap, this will automatically show the relative symbol

of snap.

Then you can select precisely the desired point without having to go every time to choose needed snap on the toolbar, comfortable isn't it?

Once set, you can enable or disable the “Autosnap” by pressing the "F3" key on the keyboard or by clicking on the dedicated button on the Bottom bar.

(On older AutoCAD by clicking on the button showing the word "OSNAP" on the bottom bar).

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On newer AutoCAD clicking the arrow beside the “sanp” button on the bottom bar, you can set the automatic snap in menu that appears, or access to

the window “Object Snap Settings...”

These tools are essential to draw with precision, do some tests, drawing lines and joining them with the other, with both AutoSnap and singular snap at

once.

When you select the snap individually, note that on the command line is written the newly activated, which will be valid only for next selection.

If you select the wrong snap, you can choose another by clicking on it twice. (Look always on the command line that tells you what you choose).

With the AutoSnap active, you can also temporarily select a different snap than those set automatically, by selecting it on the toolbar.

In this case, it will be active for only one selection.

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“Move” command.

The move command, as the name suggests, is use to move one or more objects from one point to another of the drawing.

It is activated by clicking on this icon which is on the "modify" toolbar.

At this point, the crosshair cursor changes to a selection handle and on the “command line” is write, “select objects”.

You must now select one or more objects to move and you can do so by clicking on each one individually or by selecting one or more windows, then

we need to confirm your selection by pressing Enter or the right mouse button.

Please note, before pressing enter you can remove items from the selection made, by holding down the “shift” key on the keyboard and simultaneously

selecting objects to remove, individually or with a selection window.

This is a general concept to remember, regardless of use by various commands in AutoCAD, (I mean also without start any command) you can select

objects by clicking on it and deselect it again by clicking while holding down the “shift”, or by pressing “esc” you deselect all.

The selected objects change their appearance becoming highlighted.

Once you have selected and confirmed the items to be moved AutoCAD ask us to establish two points, clicking with the mouse:

- The starting point from which move objects.

- The destination point where we are going to put objects, relatively to the first point selected.

This means that if you move such as a square, you can select as a first point of displacement, an angle of the object (using the snap), or even a point

outside the object, as the vertex of another object or a random point on drawing area.

I hope you understand this concept well and I get a picture to help you:

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Well, if you want to move the blue square under the red, but maintaining the distance (A) between them, you can select as the first move point a corner

of the green square and the same corner as the second point on the red square.

If you want to attach the blue square below the red, will be choose as a first point one of the two vertices on the top of blue square and as second point one of the two vertices in the bottom of the red square.

Summary:

1) Activating the command ‘move’

2) Selecting objects to move

3) Confirm selection by pressing Enter or the right mouse button

4) Select the first point of reference

5) Select the second point of destination and exit the command.

Make some tests...

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“Copy”command.

The command "copy" at this point is very simple because it works exactly like the "move" but instead of moving the selected object, it makes a

copy of this.

The only difference is that once copied the first object, the command does not end and you can continue to make copies of the object, until you press

the Enter key to exit the command.

This command is on the “modify” toolbar, and then allows us to copy objects within each drawing.

Not to be confused then with the commands “copy, cut, paste” of Windows, which are also present in AutoCAD, but may be used to copy objects

between two different designs.

At this point, I want to speak again of the overlapping objects.

As seen above, with the copy command you can make multiple copies of one or more objects, doing what you can create copies of objects over

themselves while continuing to display only one screen.

Creation of overlapping lines do not give particular problems, but is good to try to avoid them.

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“Rotate”command.

The "rotate" command is used to rotate the selected objects according to the desired value, expressed in degrees.

By clicking on the respective command on the modify toolbar, the program prompts you to select the object or objects to rotate, once selected hit

Enter or the right mouse button to confirm them.

At this point AutoCAD, similar to the move command, ask us to specify the base point, which in this case represents the axis of rotation, than is the

axis respect to which the previously selected objects will be rotate.

Again, you can choose a fixed point in an object by use of “snap” (a corner, the end of a line, the center of a curve, etc.) or a random point in the

drawing area.

Once you click and set the axis of rotation, the command line shows: “Specify rotation angle”, it must then enter the value of what we want the object

to be rotate, for example 45 degrees.

Type 45 with the keyboard, then hit Enter, the objects are rotate and the command ends automatically.

The direction of rotation, by including positive values will be of type “Counter clockwise” in AutoCAD is set as the default so if you want to rotate

“Clockwise” will be sufficient to enter negative numbers: -45.

You can enter rotation angles from 0 ° to 360 ° both positive and negative (of course do not rotate an object 360 degrees because it amounts to not

rotate), using as many decimal points you want e.g. 45.99 ° or 15.2 or 30.671.

This at least in theory, then in practice you usually use whole numbers or with one decimal value, also depends on what you draw.

(In AutoCAD the comma, separating the decimal numbers is done by inserting a dot). I repeat:

If you add numbers with decimal values must be used the dot and not commas. Ex 10.25 is ok but 10,25 is not correct!

Summary:

1. Click on the "rotate" command .

2. Select the objects to rotate.

3. Press Enter or right mouse button to confirm the selection.

4. Establish the pivot point on the design by clicking with the mouse.

5. Type on the keyboard the number of degrees you want, positive or negative.

6. Press Enter or right mouse button. The rotation is performed and the command is finished.

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“Scale”command.

The Scale command serves to enlarge or reduce objects.

It is also located on the "Modify" toolbar, and work similarly to the last seen.

Starts the tool, select the objects to scale, then press Enter to confirm the selection made and then you have to choose again the basic point of reference,

under which the objects will be scaled.

AutoCAD asks now the numerical value to what we want to scale the selected objects, on the command line shows: “Specify scale factor”.

You can enter decimal or integer values, for example if you want to enlarge twice selected objects will enter a value of 2, but if you want to halve the

size will fit 0.5 and so on, ten times greater with 10… and 0.1 will reduce to one-tenth the size etc.

Once inserted the desired value, you hit return or the right mouse button, the objects are scaled and exits the command.

Summary:

1. You click on the "scale" .

2. Select the objects to scale.

3. Press Enter or right mouse button to confirm the selection.

4. Establish the basic point of reference making click with the mouse.

5. Type on the keyboard the scale factor.

6. Press Enter or right mouse button, the change is doneand the command is completed.

On the “scale” tool it is necessary to dwell further because although simple to use is often a source of difficulty for those beginning.

One of the more complicated steps to understand is the determination of the correct "scaling factor" to be used when you want to make an enlarged

detail of an object.

Suppose you have drawn a table and you want to make an enlarged detail of this. What scale factor should we use?

It must take account of the scale for which we will print our design.

Normally the technical drawings made with AutoCAD, should be printed in scale, 1:10, 1:20, 1:100, and so on when needed.

In the case of a table, the design that we are going to print may be done in a scale of 1:10, in this case if you want to make the drawing a detail, that is

once printed in the scale 1:1 (true) , will have to be scaled by 10 times compared to the basic design.

If you want to print the table in 1:20 scale, you must enlarge the detail of 20 times compared to the basic design, which would otherwise result in a 1:2.

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“Mirror”command.

The mirror command is very useful for creating a mirror copy of one or more objects relative to an axis to be determined.

After you click the tool, you must select the objects to "mirror", you select one or more items and then you press "enter" key or the right mouse button

to confirm them.

At this point it appears on the command line 'select first point of mirror line'.

You must indicate two points which determine the axis under which the objects will be mirrored, these points can be selected on objects already drawn

(using snap features) or randomly on the area of the screen, so orthogonal or not .

After selecting the second point, we are asked "erase source objects?".

In this case we will respond by typing on the keyboard "y" or "n" (which stand for Yes or Not), then press 'enter', the mirror is executed and the

command is completed.

According to the choice we made, will run the mirror to keep or delete the selected items first.

You do not have that choice every time, Autocad has set the default "n" that keeps the source objects, and in any case remember your last choice and it

shows on the command line, so it got to this point, most of times, just press Enter to confirm the setting already there.

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“Stretch”command.

The command 'stretch' used to modify the objects already drawn, in practice it stretches the part we're going to select on them.

Draw a random figure of four sides, a square or a random geometry.

By clicking on the “stretch” activates the command and you must then make a selection area on the object to be modify, including in the case of a

square, one or two vertices.

The stretch tool it will act only on the vertices of the objects, which included within the selection window. Then click the bottom right of the geometric figure, and then high above this in order to select two vertices, then press Enter key, or right click to confirm.

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You must now select the base point of displacement (as in the “move” command), which can also be a top vertex.

Try now to move the mouse whit “ortho” active or not, to see how you change the object.

Drag the object in the direction and desired position and click to set and close the command.

You can then stretch object from a vertex to a vertex of another, using the snap, or, once made the selection and move the mouse in the direction in

which enlarge the object, enter a numeric value, e.g. 50 and then press Enter key, so 50 units will enlarge the object.

All vertices of objects included in the selection area will be stretched, for example.

Imagine, for example, having to extend or raise the prospect of a cabinet you designed.

It will be possible to extend 50 units his right side, and then repeat the command by selecting only the central portion to stretch it this time 25, making

it again symmetrical. Try this just said, using just four equal squares joined to form a larger one.

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Modify first one side then the middle part to “re-center” objects by selecting the figures as shown in the picture above.

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“Align” command.

The Align command is very convenient, it allows us to align one or more objects to another and at the same time move them to a desired point.

This function has always been present in the standard AutoCAD version, but on the AutoCAD LT was introduced by the 2010 version.

How it works:

To activate the command we type the words on the keyboard 'ALIGN' and then press enter.

On the command, select one or more objects to be align and then press Enter again to confirm.

At this point, we can click on the screen for the first point of origin then the first point of destination.

Once again, click to the second point of origin and again for the second point of destination.

Done that, press return twice and selected objects will move and rotate on the points of destination.

Please note that in the alignment, first point of origin coincides with the first destination point, while the second point of origin and destination will be

utilize to determine the rotation of the objects to align, but not necessarily coincide as the location.

Example of alignment of a square, on a tilted rectangle, selecting as points of origin and destination the two lower vertices of the two figures…

Remember when you use this command to observe always the command line, which will suggest the steps to do.

Summary: 1. Type on the keyboard the command 'ALIGN' and then press Enter. 2. Select the objects to align, and press Enter to confirm. 3. Select the first point of origin and destination. 4. Select the second point of origin and destination. 5. Press return twice to carry out and complete the alignment.

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The "Undo" and "Redo" commands.

Until now we have seen some drawing and editing commands, will often have to undo the last operations performed, especially the editing operations

such as scale, stretch, etc..

In these cases we use the 'Undo' command , Which is on the standard toolbar.

Each time you press this key, Autocad undo the operations performed in sequence on the drawing of any kind they are.

In practice Autocad save all transactions made by the time we open a drawing, or do when we create a new one, all these operations can be canceled

from the last, back to start.

In the opposite way with the 'Redo' you can restore any operations that you previous canceled by pressing 'Undo' command .

A situation where it can be useful this command is as follows:

Suppose you open an existing drawing that you have to change, while retaining a copy of the current version.

After performing some changes, instead of saving the file with another name, click "Save" by mistake.

At this point the file is saved with the new changes and the old version is lost.

To retrieve just save the drawing with another name (so we will have two identical copies of the amended design), then we will use several times the

command "Undo" to go back with the changes made until we started to change design.

Now just repeat a "save as" and overwrite the first source file, so we will have recovered by undoing changes to the original back, but we will also

have the new file with the changes made, previously saved.