Hitchhiker's guide to AutoCAD - Designing with AutoCAD

There are several precision features available, including

Polar tracking. Snap to the closest preset angle and specify a distance along that angle.
Locking angles. Lock to a single, specified angle and specify a distance along that angle.
Object snaps. Snap to precise locations on existing objects, such as an endpoint of a polyline, the midpoint of a line, or the center point of a circle.
Grid snaps. Snap to increments in a rectangular grid.
Coordinate entry. Specify a location by its Cartesian or polar coordinates, either absolute or relative.

The most commonly used precision features are polar tracking, locking angles, and object snaps.

Polar Tracking

When you need to specify a point, such as when you create a line, use polar tracking to guide the movement of your cursor in certain directions.

For example, after you specify the first point of the line below, move your cursor to the right, and then enter a distance in the Command window to specify a precise horizontal length for the line.

By default, polar tracking is turned on and guides your cursor in a horizontal or vertical direction (0 or 90 degrees).

Locking Angles

If you need to draw a line at a specified angle, you can lock the angle for the next point. For example, if the second point of a line needs to be created at a 45 degree angle, you would enter <45 in the Command window.

After you move your cursor in the desired direction along the 45-degree angle, you can enter the length of the line.

Object Snaps

By far, the most important way to specify precise locations on objects is to use object snaps. In the following illustration, several different kinds of object snaps are represented by markers.

Object snaps become available during a command whenever AutoCAD prompts you to specify a point. For example, if you start a new line and move your cursor near the endpoint of an existing line, the cursor will automatically snap to it.

Set Default Object Snaps

Enter the OSNAP command to set the default object snaps, which are also called "running" object snaps. For example, you might find it useful to turn on the Midpoint object snap by default.

Recommendations

At any prompt for a point, you can specify a single object snap that overrides all other object snap settings. You hold down Shift, right-click in the drawing area, and choose an object snap from the Object Snap menu. Then move the cursor to select a location on an object.
Make sure that you zoom in close enough to avoid mistakes. In a densely populated model, snapping to the wrong object will result in an error that can propagate throughout your model.

Object Snap Tracking

During a command, you can align points both horizontally and vertically from object snap locations. In the following illustration, you first hover over endpoint 1 and then hover over endpoint 2. When you move your cursor near location 3, the cursor locks into the horizontal and vertical location shown.

You can now finish creating the line, circle, or other object that you were creating from that location.

Verify Your Work

Recheck your geometry to catch mistakes early. Enter the DIST command (or just DI) to measure the distance between any two points in your model.

For example, you might need to find the clearance between two points shown, which might represent the corner of a wall and a small table, or perhaps a 2D section of a plastic part and a wire.

After you enter DIST, click the endpoint on the corner (1). Next, hold down Shift as you right-click, and then choose Perpendicular from the object snap menu. Finally, click the circle (2).

The number of decimal places and unit style displayed in the result is controlled by the UNITS command.

Handy Function Key Reference

The keyboard function keys all have assignments in AutoCAD. The ones that are most commonly turned on and off are indicated with a key.

Note: F8 and F10 are mutually exclusive—turning either one on will turn the other one off.

When a drawing becomes visually complex, you can hide the objects that you currently do not need to see.

In the drawing below, the doors and electrical wiring were temporarily hidden by turning off their layers.

You gain this level of control by organizing the objects in your drawing on layers that are associated with a specific function or a purpose. It might be helpful to think of layers as clear plastic sheets:

With layers, you can

Associate objects by their function or location
Display or hide all related objects in a single operation
Enforce linetype, color, and other property standards for each layer

Important: Resist the temptation to create everything on one layer. Layers are the most important organizing feature available in AutoCAD drawings.

Layer Controls

To see how a drawing is organized, use the LAYER command to open the Layer Properties Manager. You can either enter LAYER or LA in the Command window, or you can click the Layer Properties tool on the ribbon.

Here's what the Layer Properties Manager displays in this drawing.

As you can see in the illustration, layer 10 WALLS is the current layer. All new objects are automatically placed on that layer. In the list of layers, the green check next to layer 10 WALLS confirms that it is the current layer.

In the column labeled On, notice that the light bulb icons for two layers are dark. These layers were turned off to hide the doors and electrical wiring in the floor plan.

Notice that each layer name starts with a two-digit number. This convention makes it easy to control the order of the layers because their order does not depend on the alphabet.

Tip: For complex drawings, you might want to consider a more elaborate layer naming standard. For example, layer names could begin with 3 digits followed by a naming code that accommodates multiple floors in a building, project numbers, sets of survey and property data, and so on.

Practical Recommendations

Layer 0 is the default layer that exists in all drawings and has some esoteric properties. Instead of using this layer, it's best to create your own layers with meaningful names.
Any drawing that contains at least one dimension object automatically includes a reserved layer named Defpoints.
Create a layer for behind-the-scenes construction geometry, reference geometry, and notes that you usually do not need to see or print.
Create a layer for layout viewports. Information about layout viewports is covered in the Layouts topic.
Create a layer for all hatches and fills. This lets you turn them all on or off in one action.

Layer Settings

The following are the most commonly used layer settings in the Layer Properties Manager. You click the icon to turn the setting on and off.

Turn off layers. You turn off layers to reduce the visual complexity of your drawing while you work.

Freeze layers. You freeze layers that you do not need to access for a while. Freezing layers is similar to turning them off, but improves performance in very large drawings.

Lock layers. You lock layers when you want to prevent accidental changes to the objects on those layers. Also, the objects on locked layers appear faded, which helps reduce the visual complexity of your drawing, but still lets you see the objects faintly.

Set default properties. You set the default properties for each layer, including color, linetype, lineweight, and transparency. New objects that you create will use these properties unless you override them. Overriding layer properties is explained later in this topic.

Controls in the Layer Properties Manager

To create a new layer, click the button shown and enter the name of the new layer. To make a different layer the current one, click the layer and then click the indicated button.

Quick Access to Layer Settings

The Layer Properties Manager takes up a lot of space, and you don't always need to access all the options. For quick access to the most common layer controls, use the controls on the ribbon. When no objects are selected, the Layers panel on the Home tab displays the name of the current layer as shown here.

Occasionally, check to make sure that the objects you create will be on the correct layer. It's easy to forget to do this, but it's also easy to set. Click the drop-down arrow to display a list of layers, and then click a layer on the list to make it the current layer. You can also click on any icon in the list to change its setting.

Maintain Your Standards

It's critically important either to establish or to conform to a company-wide layer standard. With a layer standard, drawing organization will be more logical, consistent, compatible, and maintainable over time and across departments. Layer standards are essential for team projects.

If you create a standard set of layers and save them in a drawing template file, those layers will be available when you start a new drawing, and you can start working immediately. Additional information about drawing template files is presented in the Basics topic.

Summary

Layers organize your drawing, enabling you to temporarily suppress the display of unneeded graphical data. You can also assign default properties such as color and linetype to each layer.

Note: Some experienced AutoCAD users set properties only by changing layers, while others set properties independently of layers or in combination with layers. Assigning properties to objects is covered in the Properties topic.

In the following drawing, the walls, exterior stone facing, doors, fixtures, cabinetry, HVAC, electrical, and text were created using different colors to help differentiate between them.

The Properties Palette

The Properties palette is an essential tool. You can open it with the PROPERTIES command (enter PR in the Command window), you can press Ctrl + 1, or you can click the tiny arrow in the Properties panel on the Home tab—whichever you prefer.

The Properties palette displays a list of all the important property settings. You can click any of the available fields to change the current settings. In the following example, if no objects are selected, the current color will be changed from ByLayer to Red. All subsequently created objects will then be assigned the color property Red.

Verify and Change Object Properties

You can also use the Properties palette to verify and change property settings for selected objects. If you click an object in your drawing to select it, here is what you might see in the Properties palette.

Notice that the current properties for the selected object are displayed in the Properties palette. You can change any of these properties by clicking it and changing the setting. A property that is set to "ByLayer" inherits its setting from its layer. In the previous example, the objects that were created on the 20 ELECTRICAL layer are purple because that is the default color of the objects on that layer.

If you select several objects, only their common properties are listed in the Properties palette. If you change one of these properties, all the selected objects will change in one operation. Selecting objects is covered in more detail in the Modifying topic.

Note: To clear the current selection, press Esc.

Quick Access to Property Settings

The Properties palette takes up a lot of space. For quick access to the most common properties, use the Properties panel on the ribbon. As you can see in this example, the listed properties will all be determined by the current layer.

The Properties panel works the same way as the Properties palette. When you select an object, the current property settings are replaced by the properties assigned to the selected object, and you can use this panel to easily change the properties of one of more selected objects.

Match the Properties of Objects

For a fast way to copy the properties of a selected object to other objects, use the Match Properties tool, or enter MATCHPROP or MA in the Command window.

After you click the Match Propetries tool, select the source object, and then select all of the objects that you want to modify.

Linetypes

Dashed and other non-continuous linetypes are assigned from the Properties panel. You first need to load a linetype before you can assign it.

In the Linetype drop-down list, click Other.

This action displays the Linetype Manager dialog box.

Perform the following steps:

Click Load. Choose one or more linetypes that you want to use. Notice that dashed (non-continuous) linetypes come in several preset sizes.
Click Show/Hide details to display additional settings.
Specify a different "global scale factor" for all linetypes—the larger the value, the longer the dashes and spaces. Click OK.

Once you've loaded the linetypes that you plan to use, you can select any object and specify a linetype from the Properties panel or the Properties palette. Alternatively, you can specify a default linetype for any layer in the Layer Properties Manager.

Lineweights

The Lineweight property provides a way to display different thicknesses for selected objects. The thickness of the lines remain constant regardless of the scale of the view. In a layout, lineweights display and print in real-world units.

Lineweights can also be assigned from the Properties panel.

You can leave the lineweight set to ByLayer, or you can specify a value that overrides the layer's lineweight. In some cases, the lineweight previews look the same because they are displayed in approximated pixel widths on a monitor.

Tip: It's usually best to leave lineweights turned off while you work. Heavy lineweights can obscure nearby objects when you use object snaps. You might want to turn them on for checking purposes just before you print.

To control the display of lineweights, click the Lineweight Settings button at the bottom of the lineweight list. In the Lineweight Settings dialog box, you can choose whether you want to display lineweights.

Regardless of how the lightweights appear on your monitor, objects always print at the lineweight you specify.

The most common of these tools are located on the Modify panel of the Home tab. Take a minute to look through them.

Erase

To erase an object, use the ERASE command. You can enter E in the Command window, or click the Erase tool. When you see the cursor change to a square pickbox, click each object that you want to erase, and then press Enter or the Spacebar.

Note: Alternatively, before you enter any command, you can select several objects and then press the Delete key. Experienced users often use this method as well.

Select Multiple Objects

Sometimes you need to select a large number of objects. Instead of selecting each object individually, you can select the objects in an area by clicking an empty location (1), moving your cursor right or left, and then clicking a second time (2).

With a crossing selection, any objects within or touching the green area are selected.
With a window selection, only the objects completely contained within the blue area are selected.

The result is called the selection set, which is the set of objects that will be processed by a command.

Tip: You can easily remove objects from the selection set. For example, if you select 42 objects, and two of them should not have been selected, hold down Shift and then select the two that you want to remove. Then, press Enter or the Spacebar, or right click to end the selection process.

Move and Copy

Here's how you would use the COPY command to lay out a row of decorative tiles. Starting with a polyline that represents its shape, you need to make copies that are 1/8" apart.

You click the Copy tool or enter CP in the Command window to start the command. From here, you can choose between two methods, depending on what's more convenient. You will use both these methods frequently.

The Distance Method

The second tile needs to be a total of 9-7/8" + 1/8" = 10" to the right of the original tile. So, you select the tile, press Enter or the Spacebar to end your selection, and click anywhere in the drawing area (1). This point does not have to be located on the tile.

Next, you move your cursor to the right, relying on the polar tracking angle to keep the direction horizontal, and then enter 10 for the distance. Press Enter or the Spacebar a second time to end the command.

The specified distance and a direction from the point (1) is applied to the tile that you selected.

The Two Points Method

Another method, one that you will often use when you don't want to add numbers together, requires two steps. You start the COPY command and select the tile as before, but this time you click the two endpoints as shown. These two points also define a distance and direction.

Next, to add the 1/8" space between the tiles, click the Move tool or enter M in the Command window. The MOVE command is similar to the COPY command. Select the newly copied tile, and press Enter or the Spacebar. As before, click anywhere in the drawing area and move your cursor to the right. Enter 1/8 or .125 for the distance.

Tip: The two points that define the distance and direction don't need to be located on the object that you want to copy or move. You can use two points specified anywhere in your model.

For example, enter the MOVE command. Use a selection method to select the objects in the rectangle (1). Specify a base point (2) and a second point (3) to determine the distance and direction of the move. Press Spacebar or Enter to see the results.

The distance and direction determined by the endpoints at 2 and 3 in the illustration are applied to the rectangle at the right. This is a good way to specify existing distances for moving and copying objects.

Create Multiple Copies

Similarly, you can use the two-points method as a repeating sequence. Let's say that you want to make more copies of the circle at the same horizontal distance. You start the COPY command and select the circle as shown.

Then, using the Center object snap, click the center of circle 1, followed by the center of circle 2, and so on.

For larger numbers of copies, try experimenting with the Array option of the COPY command. For example, here's a linear arrangement of deep foundation piles. From a base point, you specify number of copies and the center-to-center distance.

Offset

Most models include a lot of parallel lines and curves. Creating them is easy and efficient with the OFFSET command. Click the OFFSET tool or enter O in the Command window.

Select the object (1), specify the offset distance, and click to indicate on which side of the original that you want the result (2). Here is an example of offsetting a polyline.

Tip: A fast way to create concentric circles is to offset them.

Trim and Extend

A popular technique is to use the OFFSET command in combination with the TRIM and EXTEND commands. Trimming and extending are some of the most commonly used operations. Click the TRIM or EXTEND tool or enter TR for TRIM or EX for EXTEND in the Command window.

In the following illustration, let's say you want to extend the lines that represent the steps for this deck. You start the Extend command and select the objects to be extended (near the ends to be extended) and then press Enter or the Spacebar to end the command.

As a result, the lines are extended to the first boundary that they encounter.

If there are multiple objects to extend, you can use faster ways of selecting the objects to extend. For example

Two-point fence selection. Click an empty location (1) and then click a second location that crosses the objects to be extended (2).
Freehand selection. Click and drag an empty location (1) to another location (2).

The TRIM command follows the same steps, except that when you select the objects to trim, you select the portions to trim away.

Mirror

The following illustration comes from a tile project. The walls in this residential bathroom are flattened out to be able to lay out the tile pattern and estimate the number of tiles needed.

You can save a lot of work by taking advantage of the symmetry between the left and right walls. All you need to do is create the tiles on one wall and then mirror the wall across the center of the room.

In the example below, you start the MIRROR command (or enter MI in the Command window), use window selection (1 and 2) to select the geometry on the right wall, press Enter or the Spacebar, and then specify a mirror line (3 and 4) corresponding to the centerline of the bathroom.

Finally, decline the option to "Erase source objects" by pressing Enter or the Spacebar.

Tip: Always look for symmetry to save yourself extra work, even if the symmetry is not 100% identical.

Stretch

You can stretch most geometric objects. This lets you lengthen and shorten parts of your model. For example, this model might be a gasket or the design for a public park.

Use the STRETCH command (or enter S in the Command window) and select the objects with a crossing selection as shown below (1 and 2). The crossing selection is mandatory—only the geometry that is crossed by the crossing selection is stretched. Then click anywhere in the drawing area (3), move the cursor to the right, and enter 50 as the distance. This distance might represent millimeters or feet.

To shorten the model by a specified amount, you'd move your cursor to the left instead.

Fillet

The FILLET command (enter F in the Command window) creates a rounded corner by creating an arc that is tangent to two selected objects. Notice that the fillet is created relative to where you select the objects.

You can create a fillet between most types of geometric objects, including lines, arcs, and polyline segments.

Tip: If you hold down the Shift key when you select the second object, the result trims or extends the selected objects to a sharp corner.

Explode

The EXPLODE command (enter X in the Command window) disassociates a compound object into its component parts. You can explode objects such as polylines, hatches, and blocks (symbols).

After you explode a compound object, you can modify each resulting individual object.

Edit Polylines

You can choose from several useful options when you want to modify a polyline. The PEDIT command (enter PE in the Command window) is located on the drop-down list of the Modify panel.

With this command, you can

Join two polylines into a single polyline if they share a common endpoint
Convert lines and arcs into a polyline—simply enter PEDIT and select the line or arc
Change the width of a polyline

Tip: In some cases, the easiest method to modify a polyline is to explode it, make the modifications, and then turn the objects back into a polyline using the Join option of the PEDIT command.

Grips

Grips are displayed when you select an object without starting a command. Grips are often handy for light editing. For example, the line below accidentally snapped to the wrong endpoint. You can select the misaligned line, click on a grip and then click to specify the correct location.

By default, when you click a grip, you automatically start in **STRETCH** mode as indicated in the Command window. If you want to explore other ways of editing objects with grips, press Enter or the Spacebar to cycle through several other editing modes. Some people perform many editing operations using grips.

Some Basic Definitions

In AutoCAD, symbols and details that you insert into drawings are called blocks. A block is a collection of geometric and text objects plus other data that are combined into a single named object. The following are some examples of a variety of blocks at different scales.

There are four things involved for inserting blocks in a drawing.

A block definition. This data is stored in a drawing file or drawing template file in a non-graphical format. Block definitions can easily be created or imported from any drawing file.
A block reference. When you insert a block, you specify a drawing file or a block definition to import. The graphics for the block reference are generated from the block definition.
A block insertion base point or just base point. When you insert a block, this is the part of the block attached to your cursor.

The base point is circled on the block below. Later, if you select a block that's already been inserted, it displays a grip at the base point. You can easily move and rotate this block using this grip.

A block insertion tool. Several different tools are available in the product. These include the block gallery on the ribbon, the Blocks palette, the Tool Palettes window, and Autodesk Design Center.

For example, the following drawing contains only four block definitions: Cubicle, Chair, Table, and Plant. There are three block references to Cubicle, twelve block references to Chair, two block references to Table, and two block references to Plant.

Considering this example, what are the advantages of inserting the chair as a block reference 12 times rather than creating 12 copies of a geometry of the chair?

The block reference of the chair associates the geometry of the chair into a single object, which is easier to move, copy, and rotate as a unit.
The part number, vendor, and other information, which are called block attributes, can be stored with the block definition or each block insertion. This data can be extracted into a schedule or a report.
If you make a change to the block definition in a drawing, all the associated block references in the drawing are immediately updated.
For drawings with many repetitive elements, the amount of data stored is significantly less when these elements are stored as block references.

Note: The commonly used term, block, can refer loosely to either a block definition, a block reference, or both depending on the context.

Insert Blocks into a Drawing

Typically, you insert a block into the current drawing from one of these sources:

Any drawing file. For example, you might create a drawing of a standard detail view. You can then use a block insertion tool to insert this drawing as a block into your current drawing. In this example, the detail views folder is commonly termed a block library folder.

One or more block definitions contained within a drawing file. For example, you can create a drawing that only contains block definitions of trees. You can then insert any of these blocks from that drawing into your current drawing. A drawing file that contains a family of related blocks is commonly termed a block library drawing.

One or more block definitions created in your current drawing. For example, you might want to create a block from a set of objects that appear repeatedly in that drawing, such as the following cubicle arrangement that contains multiple nested blocks. All the blocks used in the cubicle arrangement can be combined into a single block for multiple placements.

Once you insert a block, you can easily move, copy, rotate or scale it as a single unit.

Use a Block Insertion Tool

To get started with the Blocks palette, follow these steps:

Click Insert from the Home tab and click Blocks from Libraries. This starts the BLOCKSPALETTE command.

This action opens the Blocks palette to the Libraries tab.

Note: The first time Blocks from Libraries is clicked, a file selection dialog box opens where you can select an initial block library drawing.

Click the Browse button to display a folder or file selection dialog box.
Navigate to the DesignCenter folder where a variety of sample drawings are stored.

Each drawing in the DesignCenter folder contains a set of related block definitions.
Select a drawing file that interests you.

For example, let's say you create drawings for heating, ventilation, and air conditioning. Select the HVAC drawing and then click Open.

From the Blocks palette, Libraries tab, click and place several of the blocks.

This action copies the selected block definition from the block library drawing into your current drawing and inserts a block reference. Inserting additional block references will now be much faster. To specify a different drawing file, use the Browse control as before.
To choose a different library drawing from the DesignCenter folder, make sure that the Libraries tab is current (1) and click the file navigation button (2).

Note: You can also navigate directly to a drawing file to insert as a block.
Experiment with the other controls. For example, try changing the preview control.

Tip: The default options at the bottom of the Blocks palette are usually acceptable, but you can experiment with them to see what options you might want to use.

Notice that the next time you click Insert on the ribbon, the gallery displays all of the block definitions stored in the current drawing. You can quickly click and place these blocks from the gallery into your drawing.

Also, familiarize yourself with the Blocks palette tabs.

The Current Drawing tab displays all of the block definitions in the current drawing only.
The Recent tab displays the block definitions that you've recently inserted or created in the current and previous sessions. These blocks can come from various drawings.
The Favorites tab displays blocks you've copied to this tab. To copy a block to the Favorites tab, right-click a block on one of the other tabs and select Copy to Favorites.

Create a Drawing for Use as a Block

Often, individual drawing files are created to be used as blocks and saved in a folder with similar drawing files. This method is an alternative to accessing the block definitions stored in a single drawing.

Note: You can store your block drawings on cloud storage so that you have access to them across devices.

When you create a drawing file for use as a block, make sure that you locate an object at the origin point (0,0). This will serve as the default base point of the block. Later, when you insert the block, it is attached to your cursor at the base point.

In the following example, a drawing file is inserted into the current drawing to provide a standard detail view.

Custom title blocks and drawing borders are also created as drawing files that can be inserted later or included in drawing template files.

Tip: When you save drawings for later insertion, navigate to a folder, right-click, and create several folders to organize the drawings. You can drag one or more of them into your Places bar for easier access in the future.

Manage Block Definitions and Data in a Drawing (Optional)

You can create, remove, and modify block definitions directly in the current drawing for special circumstances.

Remove unused block definitions from a drawing with the PURGE command. Purging a drawing of unused block definitions can reduce the size of a drawing. You can purge only those block definitions that aren't used by any block references in the drawing.
Create new block definitions directly in the current drawing with the BLOCK command. Creating block definitions is useful either if you need a block that's unique to that drawing or if you want to create a block library drawing that contains a family of related block definitions.
Disassemble a block reference into its constituent objects with the EXPLODE command. Exploding block references provides an easy way to define new versions of a block definition with the BLOCK command or to save the resulting objects to a new drawing file with the WBLOCK command.

Tip: Block definitions can also include objects called block attributes that can store information such as part number, vendor name, and cost. You can extract and export block attribute data to a table, schedule, or external file. Some blocks called dynamic blocks can change their appearance dynamically depending on the associated data, location, or options chosen.

Summary of Suggestions and Recommendations

Several different methods are commonly used for saving and organizing block definitions.

Create an individual drawing file for each block that you intend to use. Save these drawing files in folders that contain families of related drawing files.
Create drawing files called block library drawings. Each one of these drawings contains a family of related block definitions. When you insert a block library drawing into your current drawing, all the blocks that are defined in that drawing become available in your current drawing.
Include the block definitions for title blocks and commonly used symbols in your drawing template files to make them available immediately when starting a new drawing.
Evaluate which block insertion tool best suits your needs: the Blocks palette and ribbon gallery, the Tool Palettes window, or Autodesk DesignCenter.
Store your blocks on cloud storage so they are available across devices and platforms.

Tip: With online access, you can download AutoCAD drawing files from the web sites of commercial vendors and suppliers. This option can save you a significant amount of time, but always check to make sure that these drawings are drawn correctly and to scale.

Designing with AutoCAD