edt 310 - chapter 41 review - linetypes sacramento city college edt 310

EDT 310 - Chapter 4 1

Review - LinetypesReview - Linetypes

Sacramento City CollegeEDT 310

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Alphabet of Lines Alphabet of Lines The American Society of Mechanical

Engineers (ASME) has developed this standard which is accepted throughout the industry.

The Alphabet of Lines Reveals shape, size, hidden surfaces,

interior detail, alternate positions of parts, etc.

The lines differ in width and character so they are easily distinguishable.

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Review of LinetypesReview of Linetypes Object lines

Also called “visible lines”. Show the outline of an object. Are the most common type of lines used

on drawings. Are medium weight. AutoCAD calls these lines CONTINUOUS

lines.

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Visible LinesVisible Lines

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Review of LinetypesReview of Linetypes Hidden Lines

Also called dashed lines. Show features of an object that are NOT

visible in that view. Are thin lines. AutoCAD calls this linetype HIDDEN,

HIDDEN2, or HIDDENX2.

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Review of LinetypesReview of Linetypes Hidden Lines – Spacing and Size

Dashes are 0.125” long, spaced 0.06” apart.

Choose length carefully. If drawing is to be scaled down, dashes may appear too small.

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Hidden LinesHidden Lines Rules – Hidden Lines

1. If a hidden line is a continuation of a visible line then a gap is shown.

2. A gap is also shown when a hidden line crosses but does not intersect another line.

3. Hidden lines should be omitted when they are not needed for clarity.

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Hidden LinesHidden Lines

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Review of LinetypesReview of Linetypes Centerlines

Locate the centers of circles and arcs. Small dashes cross at the center of a circle. Center lines should intersect at the short

dashes. Show the axis of a cylindrical or

symmetrical shape.

Are thin lines consisting of alternately spaced long and short dashes.

Center lines extend only a short distance past the object.

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Center LinesCenter Lines Center Lines

Spacing and Size. Alternating long and short dashes

The long dash (3/4” to 1-1/2”) The short dash (1/16” to 1/8”)

AutoCAD calls this linetype CENTER, CENTER2, or CENTERX2.

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Center LinesCenter Lines Additional Rules – Center Lines

1. Small dashes cross at the center of a circle.

2. Center lines should intersect at the short dashes.

3. Center lines should extend only a short distance past the object.

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Center Lines Center Lines

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Review of LinetypesReview of Linetypes Dimension lines

Are thin lines Are placed between extension lines to

indicate a measurement. Are broken near the center for placement

of dimension numeral in mechanical drafting.

Arrows terminate the ends of dimension lines in mechanical drafting.

Are unbroken in architectural drafting. Slashes or “tic marks” are used in architectural

drafting.

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Dimension Lines, Extension Lines and LeadersDimension Lines, Extension Lines and Leaders

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Review of LinetypesReview of Linetypes Extension lines

Are thin lines. Are used to show the “extent” of a

dimension. Begin a small distance from the object and

extend 0.125” beyond the last dimension line.

May cross object lines, hidden lines and centerlines.

May not cross dimension lines.

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Review of LinetypesReview of Linetypes Extension lines

Centerlines become extension lines when they are used to show the extent of a dimension measured from a circle centerline.

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Dimension Lines, Extension Lines and LeadersDimension Lines, Extension Lines and Leaders

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Review of LinetypesReview of Linetypes Leader lines

Are thin lines Are used to connect a specific note to a

feature on a drawing. Start with a small shoulder at a note. Terminate with an arrowhead at the feature

and has a small shoulder at a note.

The AutoCAD command is LEADER or QLEADER.

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Leader LinesLeader Lines

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Cutting Plane LinesCutting Plane Lines Cutting plane and viewing plane lines

Are thick lines. Identify the location of a section.

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Cutting Plane / Viewing Plane LinesCutting Plane / Viewing Plane Lines

Cutting Plane / Viewing Plane Lines First Form – (Phantom Line Type)

Alternating long dashes (3/4” to 1 1/2”) and pairs of short dashes (1/8” with 1/16” space).

Second Form – (Hidden Line Type) Equal dashes 1/4” in length.

Both forms Ends bent at 90 degrees and Terminated by arrowheads to indicate the

direction of viewing of the section.

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Cutting Plane LinesCutting Plane Lines

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Viewing Plane LinesViewing Plane Lines Viewing plane lines are drawn in the same

style as cutting plane lines by identify the location of a view.

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Viewing Plane Lines Viewing Plane Lines

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Section LinesSection Lines Section lines

Are thin lines. Are drawn in a section to show where

material has been cut away.

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Section Lines Section Lines Sometimes called “cross-hatching”. Represent surfaces exposed by a cutting

plane passing through an object. Usually drawn at an angle of 45o.

Spacing and Size Space 1/8” dashes about 1/16” apart.

(small drawings - 1/32”; large drawings - 1/8”)

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Section LinesSection Lines

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Review of LinetypesReview of Linetypes Break lines

Are thick lines. Show where a portion of an object has

been removed for clarity or convenience.

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Break LinesBreak Lines Break lines

Are used to limit a partial view of a broken section.

For short breaks, a thick line is drawn freehand.

Typically used for mechanical drawings.

For long breaks, a long, thin line is drawn with breaks in the line joined by freehand “zig-zags”.

Typically used for architectural drawings.

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Break LinesBreak Lines Break lines

AutoCAD does NOT produce zig-zag break lines.

They must be drawn manually.

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Break LinesBreak Lines

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Review of LinetypesReview of Linetypes Phantom lines

Are thin lines Are a long dash alternating with two short

dashes alternating with long dash.

Phantom lines show: Alternate positions. Repeated details. Paths of motion.

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Phantom LinesPhantom Lines Phantom Lines

Spacing and Size Thin, long dashes 3/4” to 1-1/2” in length alternating with pairs of short dashes 1/8”

long with 1/16” spacing between the dashes.

AutoCAD calls this linetype PHANTOM, PHANTOM2, or PHANTOMX2.

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Phantom Lines Phantom Lines

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Construction LinesConstruction Lines Construction Lines

Very light, gray lines. Are used to lay out all work. Light enough so they will not reproduce

when making a print. On drawings for display or photo

reproduction, they should not be visible beyond an arm’s length.

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Border LinesBorder Lines Border lines

Are the “frame” of the drawing. They should be the heaviest of all lines.

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Drawing Lines with AutoCADDrawing Lines with AutoCADThe LINE CommandThe LINE Command

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Drawing LinesDrawing Lines AutoCAD draws individual line segments

between two points on the screen.

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The LINE CommandThe LINE Command To draw lines with AutoCAD

Type “L” or “LINE” at the Command: prompt.

Or Pick the LINE button from the Draw Toobar

Or Pick LINE in the Draw Pull-Down Menu

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The LINE CommandThe LINE Command When you use LINE,

A prompt asks you to pick a starting point. Select a first point with your left mouse

button. Select a second point with your left mouse

button. Select a third point with your left mouse

button.

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The LINE CommandThe LINE Command A line can be “closed” by typing “C”.

Closing a line draws a line from the last picked point to the starting point.

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Setting the Linetype Scale Setting the Linetype Scale

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Setting the Linetype ScaleSetting the Linetype Scale The linetype scale sets the length of

dashes and spaces in linetypes.

When you start AutoCAD The global linetype scale is automatically

set to match the units you select.

The global linetype scale can be overridden at the object level.

THIS IS NOT RECOMMENDED !

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Setting the Linetype ScaleSetting the Linetype Scale The default object linetype scale factor is

1.0.

Changes to the default linetype scale are made to make your drawing more closely match standard drafting practice.

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Setting the Linetype ScaleSetting the Linetype Scale A value of less than 1.0

Makes the dashes and spaces smaller.

A value greater than 1.0 Makes the dashes and spaces larger.

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Setting the Linetype ScaleSetting the Linetype Scale Experiment with the different linetype

scales until you achieve the desired results.

ALWAYS try to set linetype scale variables at the GLOBAL level first!

You may need to adjust one or two lines, but DO NOT TRY TO ADJUST ALL INDIVIDUAL LINE TYPE VARIABLES!

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Setting the Linetype ScaleSetting the Linetype Scale The Properties window lists a linetype

scale property. Change the value of individual object

linetypes with this box.

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The LTSCALE VariableThe LTSCALE Variable

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The LTSCALE VariableThe LTSCALE Variable The LTSCALE variable

Affects the entire drawing. The default value is 1.0. The drawing REGENERATES after

changing the LTSCALE variable.

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Coordinate SystemsCoordinate SystemsCartesian, Relative and PolarCartesian, Relative and Polar

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Point Entry ModePoint Entry Mode Each of the point entry methods uses the

Cartesian coordinate system.

The Cartesian coordinate system is based on selecting distances from three intersecting axes, X, Y, and Z.

A location is defined by its distance in x,y from the origin point.

Most of our work will be in 2D not 3D.

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The Cartesian Coordinate SystemThe Cartesian Coordinate System The Origin divides the coordinate system

into four quadrants.

Points are located in relation to the origin.

The Origin is point 0,0 and is the location where the X and Y axes cross.

For AutoCAD, the origin is the lower-left of your drawing.

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Origin (0,0)

Quadrant 1

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The Cartesian Coordinate SystemThe Cartesian Coordinate System

Quadrant #1

+x, +y

Quadrant #3

-x, -y

Quadrant #2

-x, +y

Quadrant #4

+x, -y

Origin (0,0)

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Using Absolute CoordinatesUsing Absolute Coordinates Points are measured from the origin.

A point [4,2] is 4 units in the X direction. 2 units in the Y direction. from the origin.

The coordinate display on the lower left corner of the screen shows the location of the cursor at any time.

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Using Absolute CoordinatesUsing Absolute Coordinates You can draw lines by typing in the

coordinates of the line. Command: L or LINE Specify first point: 4,2 Specify next point or [Undo]: 7,2 Specify next point or [Undo]: 7,6 Specify next point or [Undo]: 4,6 Specify next point or [Undo]: 4,2 Specify next point or [Undo]: [Enter] Command:

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Using Relative CoordinatesUsing Relative Coordinates Relative coordinates are located from the

previous position, rather than from the origin.

The “@” symbol must precede each entry.

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Using Relative CoordinatesUsing Relative Coordinates Command: Specify first point: 2,2 Specify next point or [Undo]: @6,0 Specify next point or [Undo]: @2,2 Specify next point or [Undo]: @0,3 Specify next point or [Undo]: @0,3 Specify next point or [Undo]: @-2,2 Specify next point or [Undo]: @-6,0 Specify next point or [Undo]: [Enter] Command:

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Using Polar CoordinatesUsing Polar Coordinates A point located using polar coordinates is

based on the distance from a fixed point (@6 at a given angle (< 45)

Procedure: Enter the distance

then Enter the angle Example: @6<45

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Using Polar CoordinatesUsing Polar Coordinates The angular values used for polar

coordinates are: 0 = east (or to the right) 90 = North (or up) 180 = West (or to the left) 270 = South (or down).

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Using Polar CoordinatesUsing Polar Coordinates @4<45 means

Measure from the previous point A distance of 4 At an angle of 45 degrees from 0 degrees.

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The Coordinate DisplayThe Coordinate Display

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The Coordinate DisplayThe Coordinate Display The coordinate display shows the current

cursor location.

Turn the cursor tracking display on and off with the [F6] key.

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The COORDS VariableThe COORDS Variable The COORDS variable lets you choose

how the coordinates will be displayed. 0 = the coordinate display is static.

Coordinates are displayed only when points are selected.

1 = the coordinate display is dynamic.

2 = the coordinate display is in polar mode showing length at an angle.