Transcript Object_Snap.ppt

Object Snap
Sacramento City College
Engineering Design Technology
Object Snap
1
Objectives
 Use
OSNAP to create precision drawings
 Use object snap overrides for single point
selections
 Set running object snap modes for
continuous use
 Adjust aperture size based on point
selection needs
Object Snap
2
Objectives
 Use
Tracking to locate points relative to
other points in a drawing
Object Snap
3
OSNAP
Object Snap
4
OSNAP
 The
OSNAP feature of AutoCAD
 Means
object snap
 Refers to the ability to “snap” exactly to a
specific point or place on an object.
 Endpoint
of line
 Midpoint of line
 Centerpoint of circle
Object Snap
5
AutoSnap
 Visual
cues indicate when AutoCAD has
selected an OSNAP.
 Endpoint Cue
A
square when the cursor is placed near the
object.
 Midpoint
Cue
A
triangle when the cursor is placed near the
object.
Object Snap
6
Object Snap
7
The Object Snap Modes
 Object
snap modes determine the point to
which the cursor snaps.
Object Snap
8
Setting Running Object Snaps
Object Snap
9
Setting Running Object Snaps
 Set
the running object snaps.
 “Preset”
object snap modes
 AutoCAD
automatically activates them at
all point selection prompts.
Object Snap
10
Setting Running Object Snaps
 Set
by
 1.
OSNAP at Command: prompt
 2. Pick Object Snap Settings button from the
Object Snap toolbar
Object Snap
11
Object Snap
12
Object Snap Modes
Object Snap
13
Object Snap Modes
 Endpoint
- finds the nearest endpoint of a
line, arc, elliptical arc, spline, ellipse, ray,
solid or multiline.
 Midpoint
- finds the middle point of any
object, having two endpoints, such as a
line, arc, elliptical arc, spline, ellipse, ray
solid, xline or multiline.
Object Snap
14
Object Snap
15
Object Snap Modes
 Center
- locates the center point of a
radial object, including circles, arcs,
ellipses, elliptical arcs, radial solids.
Object Snap
16
Object Snap
17
Object Snap Modes
 Quadrant
- picks the closest of the four
quadrant points that can be found on
circles, arcs, elliptical arcs, ellipses, and
radial solids.
 Intersection
intersection.
- picks the closest
Object Snap
18
Object Snap
19
Object Snap
20
Object Snap Modes
 Apparent
Intersection - selects a visual
intersection between two objects that
appear to intersect on the screen, but may
not intersect in 3d space.
Object Snap
21
Object Snap
22
Endpoint Object Snap
 Endpoint
Object Snap
 This
snap setting is often selected as a
running object snap
 Type END at the prompt
 Pick the Endpoint button
 Select Endpoint from the cursor menu
 Prompt is a small square
Object Snap
23
Midpoint Object Snap
 Midpoint
 Finds
and picks the midpoint of a line,
polyline, or arc.
 Type MID at the prompt
 Pick the Midpoint button
 Select Midpoint from the cursor menu
 Position cursor near the midpoint of the object
 Prompt is a small triangle marks the midpoint
where the line will snap
Object Snap
24
Center Object Snap
 Center
option
 Snaps
to the center point of a circle,
doughnut, ellipse, elliptical arc or arc
 Type CEN
 Pick Center button
 Pick Center from the cursor menu
 Locate the cursor near the object whose
center is to be located
 Prompt is a small circle
Object Snap
25
Quadrant Object Snap
A
quadrant is a quarter section of a circle,
doughnut, ellipse, elliptical arc or arc.
 The Quadrant object snap mode finds the
0o, 90o, 180o and 270o positions on these
objects.
 Move cursor near one of these locations to
snap to them
Object Snap
26
Intersection Object Snap
 The
Intersection Option is used to snap to
the intersection of two or more objects.
 Type
INT
 Pick Intersect Button
 Pick Intersection from the cursor menu
A
small ‘x’ marks the intersection
 Only
appears when the cursor is close to the
intersection point of the two objects
Object Snap
27
Intersection Object Snap
 If
the cursor is near an object but not
close to an actual intersection, the
SnapTip reads Extended Intersection
 AutoCAD
finds a projected intersection
point of the two objects.
 Very
useful when two objects do not intersect.
Object Snap
28
Apparent Intersection OSNAP
 The
apparent intersection is the point
where two objects appear to intersect
based on the currently displayed view.
 Three-dimensional objects that are far
apart may appear to intersect on the
screen.
 This is a valuable option when working
with 3D drawings.
Object Snap
29
Object Snap
30
Perpendicular Object Snap
 Allows
you to draw one object
perpendicular to another object
 Type
PER at the selection prompt
 Pick Perpendicular button
 Pick Perpendicular from the cursor menu
Object Snap
31
Object Snap
32
Perpendicular Object Snap
A
deferred perpendicular means the
calculation of the perpendicular point is
delayed until another point is picked.
Object Snap
33
Perpendicular Object Snap
 Perpendicular
is calculated from points
picked, not as a relationship between
objects.
 Perpendicularity
is measured at the point
of intersection so it is possible to draw a
line that is perpendicular to a circle or an
arc.
Object Snap
34
Tangent Object Snap
 Tangent
Object Snap is similar to the
Perpendicular Object Snap
 Aligns
objects tangentially.
 Type TAN at the selection prompt
 Pick Tangent from the cursor menu
 Pick Tangent button
Object Snap
35
Tangent Object Snap
 When
creating an object that is tangent to
another object, multiple points may be
needed to fix the tangency point
 Until
both points have been specified, the
object snap specification is for deferred
tangency
Object Snap
36
Parallel Object Snap
 Allows
you to find any point along an
imaginary line that is parallel to an
existing line or polyline.
 Type
PAR at the selection prompt
 Pick Parallel from the cursor menu
 Pick Parallel button
 Parallel
OSNAP is similar to Extension
because it requires more than one
selection point.
Object Snap
37
Object Snap
38
Object Snap
39
Object Snap
40
Object Snap
41
Node Object Snap
 Point
objects can be snapped to using the
Node object snap mode.
 The
point must be in visible display mode
Object Snap
42
Nearest Object Snap
 Use
to specify a point on an object but
which cannot be specified from any of the
other snap modes.
 Use
when you want an object to touch an
existing object, but the location of the
intersection is not critical
Object Snap
43
OSNAP Overrides
Object Snap
44
Object Snap Override
 An
object snap override can be obtained
from
 The
Object Snap Override menu activated by
[Shift-Right-Click].
 The Object Snap toolbar.
 Typed in from the keyboard.
Object Snap
45
Object Snap Override
 OSNAP
Overrides
 Is
the entry of an object snap mode at a point
specification prompt.
 Are active for one point specification only,
 Override any previously set object snap
modes for that entry.
Object Snap
46
Overriding Running Object Snaps
 Running
object snap
 Is
always active if OSNAP is ON.
 is suspended with an object snap override.
 To
make a single point selection without the
effects of any running object snap, enter the
None object snap mode
Object Snap
47
OSNAP ON/OFF
Object Snap
48
OSNAP ON/OFF
 Object
 The
snap On/Off
button at the bottom of the screen
 F3
Object Snap
49
Multiple OSNAPs
Object Snap
50
Using Multiple Object Snaps
 More
than one object snap mode can be
made active at once.
 When more than one is active, AutoCAD
picks the closest point.
 This
can cause conflicts !
Object Snap
51
Using Multiple Object Snaps
 OSNAP
 CEN
Conflict Example
and QUA conflict with each other.
 No
matter where you pick a circle, the closest
quadrant point is always closer than the
center of the circle.
 So
 When
quadrant and circle are both set active,
a quadrant point is always picked.
Object Snap
52
Using Multiple Object Snaps
 OSNAP
Conflict Example
 NEA
(Nearest)
 Conflicts with almost every other mode.
 Nearest mode always locates the point
closest to the current cursor location.
Object Snap
53
Using Multiple Object Snaps
 The
Tab key can be used to cycle through
available snap points.
 Press
the Tab key repeatedly until the desired
point is marked.
Object Snap
54
Changing the Aperture Size
Object Snap
55
Changing the Aperture Size
 When
selecting a point with OSNAP, the
cursor must be within a specific range to a
point before it is located.
 This
square area is called the aperture and
is invisible by default
 To
display the aperture, pick the AutoSNAP
tab and activate the Display aperture box
check box
Object Snap
56
Changing the Aperture Size
 The
aperture size can also be set from the
Command prompt
Command: APERTURE
Object snap target height (1-50 pixels)
Command:
Object Snap
57
AutoSnap Settings
Object Snap
58
AutoSnap Settings
 AutoSnap
options
 Additional
visual cues can be turned off
 The appearance of AutoSnap and
functionality can also be changed
Object Snap
59
AutoSnap Settings
 Marker
- toggles the AutoSnap marker
 Magnet - toggles the AutoSnap magnet
 When
active, the magnet snaps the cursor to the
object snap point.
 SnapTip
- toggles the SnapTip display
 Display aperture box - toggles the display of
the aperture box
 Marker color - changes color of marker
 Marker size - changes marker size
Object Snap
60
Object Snap
61
Tracking
Object Snap
62
Tracking
 Tracking
allows you to visually locate
points in a drawing relative to other points
 To activate Tracking
 Pick
the Tracking button from the Object Snap
toolbar
 Type TK or TRA at the point selection prompt
 Pick Tracking from the cursor menu
Object Snap
63
Tracking - Example
 Tracking
allows you to visually place a
circle at the center of a rectangle
Object Snap
64
Tracking - Example
 Command:
C or CIRCLE
 3P/2P/TTR/<Center point>: TRA
 First tracking point: MID (pick one of the
vertical lines and move the cursor
horizontally)
 Next point: (pick one of the horizontal lines)
 Next point: (press Enter to end tracking)
 Diameter/<Radius><0.2500>:
 Command:
Object Snap
65
Tracking
 Once
started, Tracking remains active until
you press [Enter] at a Next point: prompt
 The
cursor locks to the axis you first move
along.
 If you desire to select another axis, move
back to the first point, then move in the
perpendicular direction
Object Snap
66
Polar Tracking
 Polar
tracking works similar to ORTHO but
has a wider range of options.
 ORTHO
and Polar cannot be used at the
same time.
 The
cursor snaps to preset incremental
angles when a point is being located.
Object Snap
67
Object Snap
68