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EDT 310 - Chapter 4 1
Review - LinetypesReview - Linetypes
Sacramento City CollegeEDT 310
EDT 310 - Chapter 4 2
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.
EDT 310 - Chapter 4 3
EDT 310 - Chapter 4 4
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.
EDT 310 - Chapter 4 5
Visible LinesVisible Lines
EDT 310 - Chapter 4 6
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.
EDT 310 - Chapter 4 7
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.
EDT 310 - Chapter 4 8
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.
EDT 310 - Chapter 4 9
Hidden LinesHidden Lines
EDT 310 - Chapter 4 10
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.
EDT 310 - Chapter 4 11
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.
EDT 310 - Chapter 4 12
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.
EDT 310 - Chapter 4 13
Center Lines Center Lines
EDT 310 - Chapter 4 14
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.
EDT 310 - Chapter 4 15
Dimension Lines, Extension Lines and LeadersDimension Lines, Extension Lines and Leaders
EDT 310 - Chapter 4 16
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.
EDT 310 - Chapter 4 17
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.
EDT 310 - Chapter 4 18
Dimension Lines, Extension Lines and LeadersDimension Lines, Extension Lines and Leaders
EDT 310 - Chapter 4 19
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.
EDT 310 - Chapter 4 20
Leader LinesLeader Lines
EDT 310 - Chapter 4 21
Cutting Plane LinesCutting Plane Lines Cutting plane and viewing plane lines
Are thick lines. Identify the location of a section.
EDT 310 - Chapter 4 22
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.
EDT 310 - Chapter 4 23
Cutting Plane LinesCutting Plane Lines
EDT 310 - Chapter 4 24
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.
EDT 310 - Chapter 4 25
Viewing Plane Lines Viewing Plane Lines
EDT 310 - Chapter 4 26
Section LinesSection Lines Section lines
Are thin lines. Are drawn in a section to show where
material has been cut away.
EDT 310 - Chapter 4 27
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”)
EDT 310 - Chapter 4 28
Section LinesSection Lines
EDT 310 - Chapter 4 29
Review of LinetypesReview of Linetypes Break lines
Are thick lines. Show where a portion of an object has
been removed for clarity or convenience.
EDT 310 - Chapter 4 30
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.
EDT 310 - Chapter 4 31
Break LinesBreak Lines Break lines
AutoCAD does NOT produce zig-zag break lines.
They must be drawn manually.
EDT 310 - Chapter 4 32
Break LinesBreak Lines
EDT 310 - Chapter 4 33
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.
EDT 310 - Chapter 4 34
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.
EDT 310 - Chapter 4 35
Phantom Lines Phantom Lines
EDT 310 - Chapter 4 36
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.
EDT 310 - Chapter 4 37
Border LinesBorder Lines Border lines
Are the “frame” of the drawing. They should be the heaviest of all lines.
EDT 310 - Chapter 4 38
Drawing Lines with AutoCADDrawing Lines with AutoCADThe LINE CommandThe LINE Command
EDT 310 - Chapter 4 39
Drawing LinesDrawing Lines AutoCAD draws individual line segments
between two points on the screen.
EDT 310 - Chapter 4 40
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
EDT 310 - Chapter 4 41
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.
EDT 310 - Chapter 4 42
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.
EDT 310 - Chapter 4 43
Setting the Linetype Scale Setting the Linetype Scale
EDT 310 - Chapter 4 44
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 !
EDT 310 - Chapter 4 45
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.
EDT 310 - Chapter 4 46
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.
EDT 310 - Chapter 4 47
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!
EDT 310 - Chapter 4 48
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.
EDT 310 - Chapter 4 49
The LTSCALE VariableThe LTSCALE Variable
EDT 310 - Chapter 4 50
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.
EDT 310 - Chapter 4 51
EDT 310 - Chapter 4 52
Coordinate SystemsCoordinate SystemsCartesian, Relative and PolarCartesian, Relative and Polar
EDT 310 - Chapter 4 53
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.
EDT 310 - Chapter 4 54
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.
EDT 310 - Chapter 4 55
Origin (0,0)
Quadrant 1
EDT 310 - Chapter 4 56
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)
EDT 310 - Chapter 4 57
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.
EDT 310 - Chapter 4 58
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:
EDT 310 - Chapter 4 59
Using Relative CoordinatesUsing Relative Coordinates Relative coordinates are located from the
previous position, rather than from the origin.
The “@” symbol must precede each entry.
EDT 310 - Chapter 4 60
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:
EDT 310 - Chapter 4 61
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
EDT 310 - Chapter 4 62
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).
EDT 310 - Chapter 4 63
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.
EDT 310 - Chapter 4 64
The Coordinate DisplayThe Coordinate Display
EDT 310 - Chapter 4 65
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.
EDT 310 - Chapter 4 66
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.