Sacramento City College. Engineering Design Technology. Object Snap. 2. Objectives. Use OSNAP to create precision drawings. Use . object snap overrides. for single point selections. Set . running object snap modes. ID: 635852
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Object Snap
1
Object Snap
Sacramento City College
Engineering Design Technology
Slide2Object Snap
2
Objectives
Use OSNAP to create precision drawings
Use
object snap overrides
for single point selections
Set
running object snap modes
for continuous use
Use
Autotrack
and
temporary tracking modes
to locate points relative to other points in a drawing.
Slide3Object Snap
3
OSNAP
Slide4Object Snap
4
OSNAP
The
OSNAP
feature of AutoCAD
Means
object snap
It increases your drawing
performance
and
accuracy
.
Is one of the
most useful tools
in AutoCAD.
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
Slide5Object Snap
AutoTrackCreates and deletes construction lines automatically.
Object Snap
5
Slide6Object Snap
6
AutoSnap
OSNAP
Uses Visual cues
to indicate the object
snap point
that has been selected by AutoCAD.
Endpoint Cue
A
square
when the cursor is placed near the object.
Midpoint
Cue
A
triangle
when the cursor is placed near the object.
Slide7Object Snap
7
Slide8Object Snap
8
The Object Snap Modes
Two methods of activating object snaps
1. Running object snaps
2. Snap Overrides
Both display visual cues as
markers
Slide9Object Snap Modes
Object snap overridesCan be used while inside a command, however,
they are not commands. They are a “one-time” override of the OSNAP choices.Only that OSNAP choice will be active when selecting points
They can be entered 3 ways
1. Typing abbreviation at
Command:
prompt
2. Selecting from OSNAP Toolbar
3. Selecting from right-click menu
Object Snap
9
Slide10Object Snap
10
Setting Running Object Snaps
Slide11Object Snap
11
Setting Running Object Snaps
Running object snaps.
Are “preset” object snap modes
Selected by user in OSNAP dialog box by checking the “check box” for that OSNAP.
When selected, AutoCAD automatically activates them at all point selection prompts.
Slide12Object Snap
12
Setting Running Object Snaps
Set by
1. Typing
OSNAP
at
Command:
prompt
2. Pick
Object
Snap
Settings
button from the
Object
Snap
toolbar
3.
Tools > Drafting Settings
4. Right-click on the OSNAP or OTRACK button on the status bar and select Settings…
Slide13Object Snap
13
Slide14Object Snap
14
Slide15Object Snap
15
OSNAP Overrides
Slide16Object Snap
16
Object Snap Override
An
object snap override
can be obtained from
1. The Object Snap toolbar.
2. The Object Snap Override menu activated by [Shift-Right-Click].
3. Typed in from the keyboard.
Slide17Object Snap
17
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.
Slide18Object Snap
18
Slide19OSNAP Toolbar
Object Snap
19
Slide20Object Snap
20
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
Slide21Object Snap
21
OSNAP ON/OFF
Slide22Object Snap
22
OSNAP ON/OFF
Object snap On/Off
The button at the bottom of the screen
F3
Slide23Object Snap
23
Object Snap Modes
Slide24Object Snap
24
Object Snap Modes
Endpoint Object Snap
finds the
nearest endpoint
of a line, arc, elliptical arc,
spline
, ellipse, ray, solid or multiline.
This snap setting is often selected
as a running object snap.
Slide25Object Snap
25
Endpoint Object Snap
Endpoint Object Snap
Override:
Type
END
at the prompt
OR
Pick the
Endpoint
button on OSNAP Toolbar
OR
Select
Endpoint
from the right-click cursor menu
Position cursor near endpoint of the object.
Prompt
is a
small square
.
Slide26Endpoint Object Snap
Object Snap
26
Slide27Object Snap
27
ENDPOINT
Slide28Object Snap Modes
Midpoint Object Snap 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
28
Slide29Object Snap
29
Midpoint Object Snap
Midpoint Object Snap
Override:
Type
MID
at the prompt
OR
Pick the
Midpoint
button on OSNAP Toolbar
OR
Select
Midpoint
from the right- click cursor menu
Position cursor near midpoint of the object.
Prompt
is a
small triangle
marks the midpoint where the line will snap.
Slide30Midpoint Object Snap
Object Snap
30
Slide31Object Snap
31
MIDPOINT
Slide32Object Snap
32
Object Snap Modes
Center Object Snap
locates the
center point
of a radial object, including circles, arcs, ellipses, elliptical arcs, radial solids.
Slide33Object Snap
33
Center Object Snap
Center Object Snap
Override:
Type
CEN
OR
Pick
Center
button on OSNAP Toolbar
OR
Pick
Center
from the right-click cursor menu
Locate cursor near object whose center is to be located.
Prompt
is a small circle.
Slide34Center Object Snap
Object Snap
34
Slide35Object Snap
35
CENTER
Slide36Quadrant Object Snap
A quadrant is a quarter section of a circle, doughnut, ellipse, elliptical arc or arc.
Object Snap
36
Slide37Quadrant Object Snap
Quadrant Object SnapQuadrant - picks the closest of the four quadrant points that can be found on circles, arcs, elliptical arcs, ellipses, and radial solids.
0o90o
180
o
270
o
Move cursor near one of these locations to snap to them.
Object Snap
37
Slide38Quadrant Object Snap
Quadrant Object SnapOverride: Type
QUA ORPick
Quadrant Button
on OSNAP Toolbar
OR
Pick
Quadrant
from the right-click cursor menu
Prompt
is a
diamond
that marks the quadrant.
Object Snap
38
Slide39Quadrant Object Snap
Object Snap
39
Slide40Quadrant Object Snap
Object Snap
40
Slide41Object Snap
41
QUADRANT
Slide42Object Snap
42
Intersection Object Snap
Intersection Object Snap
Snaps to the intersection of two or more objects.
Override:
Type
INT
OR
Pick
Intersect Button
on OSNAP Toolbar
OR
Pick
Intersection
from the right-click cursor menu
Prompt
is a
small ‘x’
that marks the intersection
Only appears when the cursor is close to the intersection point of the two objects
Slide43Intersection Object Snap
Object Snap
43
Slide44Intersection Object Snap
Object Snap
44
Slide45Object Snap
45
INTERSECTION
Slide46Object Snap
46
Object Snap Modes
Extended Intersection
- selects an intersection point between two objects which, if they were extended, would intersect at that point.
This is useful when two objects do not actually intersect and you need to access the point where these objects would intersect if they were extended.
Is
only available as a snap override.
Slide47Extended Intersection Object Snap
Extended Intersection Object SnapTo activate Extended Intersection, select the Intersection object snap override and pick an object (rather than an intersection).
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
47
Slide48Extended Intersection Object Snap
Extended Intersection Object SnapIf the intersection point is not in the currently visible screen area, the AutoSnap
marker is not displayed when you select the second object. You can still confirm the point before picking, however. Keeping the crosshairs motionless over the second object displays the tooltip, which confirms that the objects intersect somewhere beyond the currently visible area.
Object Snap
48
Slide49Extended Intersection Object Snap
Object Snap
49
Slide50Object Snap
50
EXTENDED
INTERSECTION
Slide51Object Snap
51
Apparent Intersection OSNAP
Apparent Intersection
- selects a visual intersection between two objects that appear to intersect on the screen, but may not intersect in 3d space.
3D application only.
Slide52Object Snap
52
Apparent Intersection OSNAP
Apparent Intersection Object Snap
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
.
Not so useful for 2D.
Slide53Object Snap
53
Perpendicular Object Snap
Perpendicular Object Snap
Allows you to draw one object
perpendicular
to another object
Override
:
Type
PER
at the selection prompt
Pick
Perpendicular
button on OSNAP Toolbar
Pick
Perpendicular
from the right-click cursor menu
Prompt is a small right angle
Slide54Perpendicular Object Snap
Perpendicular Object SnapThis mode can be used with arcs, elliptical arcs, ellipses, splines,
xlines, multilines, polylines, solids, traces, or circles
Object Snap
54
Slide55Object Snap
55
Slide56Perpendicular Object Snap
Object Snap
56
Slide57Object Snap
57
Perpendicular Object Snap
A
deferred perpendicular
means the
calculation
of the
perpendicular point
is
delayed
until another point is picked.
The
second end point
determines the location of the entire line.
Slide58Object Snap
58
Perpendicular Object Snap
Important!
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.
Slide59Perpendicular Object Snap
Object Snap
59
Slide60Object Snap
60
Tangent Object Snap
Tangent Object Snap
Can use with arc, circle, ellipse, elliptical arc, and
spline
.
is similar to the Perpendicular Object Snap
Aligns objects tangentially.
Override
:
Type
TAN
at the selection prompt
Pick
Tangent
button on OSNAP Toolbar
Pick
Tangent
from the right-click cursor menu
Slide61Object Snap
61
Tangent Object Snap
When creating an object that is tangent to another object,
multiple points may be needed
to fix the tangency point.
The point at which a line is tangent to a circle cannot be found without knowing the location of
both ends
of the line.
Until both endpoints have been specified, the object snap specification is for
deferred tangency
Slide62Object Snap
62
Parallel Object Snap
Parallel Object Snap
Allows you to find any point along an imaginary line that is parallel to an existing line or
polyline.
Slide63Parallel Object Snap
Parallel Object SnapOverride:Type PAR
at the selection promptPick Parallel button on OSNAP Toolbar
Pick
Parallel
from the right-click cursor menu
Parallel OSNAP is similar to Extension because it requires more than one selection point.
Object Snap
63
Slide64Parallel Object Snap
The acquired point is found by pausing the crosshairs over any point on the line to which the new object is to be parallel. When the object is found and you move the crosshairs in a direction parallel to the existing line, a (//) symbol marks the existing line.
A dashed line, parallel to the existing line, extends from the location of the crosshairs. This line is known as the parallel alignment path.
Object Snap
64
Slide65Parallel Object Snap
The last point, which is the actual snap point, can be placed anywhere along the parallel alignment path. When the alignment path is displayed, the Parallel snap marker appears on the line from which the parallel is used.
Picking any location along the parallel alignment path creates the second point of the parallel line.
Object Snap
65
Slide66Parallel Object Snap
Object Snap
66
Slide67Object Snap
67
Slide68Object Snap
68
Slide69Object Snap
69
Slide70Object Snap
70
Slide71Object Snap
71
Node Object Snap
Node Object Snap
POINT objects
can be snapped to using the
Node
object snap mode.
To FIND the POINT, the POINT must be in
visible display mode.
Affected by setting of the PDMODE system variable.
Slide72Object Snap
72
Nearest Object Snap
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
Slide73Nearest Object Snap
Nearest Object SnapExample: Consider drawing a line object that is to end on another line.
Trying to pick the point with the crosshairs is inaccurate because you are relying only on your screen and mouse resolution. The line you draw may fall short or extend past the line.
Using Nearest ensures that the point is precisely on the object.
Object Snap
73
Slide74Object Snap
74
Multiple OSNAPs
Slide75Object Snap
75
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
!
Slide76Object Snap
76
Using Multiple Object Snaps
OSNAP Conflict Example
CEN 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.
Slide77Object Snap
77
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.
Slide78Object Snap
78
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.
Slide79Object Snap
79
Changing the Aperture Size
Slide80Object Snap
80
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.
The object snap detection system finds everything within a
square area
centered at the crosshairs location.
This
square area
is called the
aperture
and is
invisible by default
.
Slide81Changing the Aperture Size
ApertureTo display the aperture, pick the AutoSNAP tab and activate the
Display aperture box check box.Aperture box size is measured in pixels
Object Snap
81
Slide82Object Snap
82
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:
Slide83Object Snap
83
AutoSnap Settings
Slide84Object Snap
84
AutoSnap Settings
AutoSnap options
Additional visual cues can be turned off
The appearance of AutoSnap and functionality can also be changed
Slide85Object Snap
85
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
Slide86Object Snap
86
Slide87Object Snap
87
Object Snap Tracking
Slide88Object Snap
88
Object Snap Tracking
Object
SnapTracking
allows you to visually locate points in a drawing relative to other points.
When this mode is active, placing the crosshairs near an
AutoSnap
marker acquires the point.
After a point is acquired, horizontal and vertical alignment paths are available for locating points.
Slide89Object Snap Tracking
To activate Tracking1. Pick the Tracking button
from the Object Snap toolbar2. Type TK or
TRA
at the point selection prompt. Pick
Tracking
from the cursor menu.
3. F11
4. OTRACK button on the status bar.
Object Snap
89
Slide90Object Snap Tracking
Tracking is only available for points selected by the currently active object snap modes
.
Object Snap
90
Slide91Object Snap
91
Object Snap Tracking
Object snap tracking can also be used to position new geometry based on the locations of existing geometry.
Slide92Object Snap Tracking
Example:In the next slide, Object snap tracking is used to position a circle directly above the midpoint of a horizontal line and to the right of the midpoint of an angled line, with only the Midpoint running object snap on.
The OSNAP and OTRACK buttons on the status bar are active.
Object Snap
92
Slide93Object Snap Tracking
Object Snap
93
Slide94Object Snap
94
Object Snap Tracking
Command: C or
CIRCLE
Specify center point for circle or [Undo]: (pause the crosshairs near the midpoint of the horizontal line to acquire it, arid then pause the crosshairs near the midpoint of the angled line to acquire it. Move the crosshairs to the position as shown in the second step until two tracking vectors appear. Pick to locate the center of the circle.)
Specify radius of circle or [Undo]: (drag the crosshairs to specify any radius and pick to complete the circle)
Command:
Slide95Object Snap
95
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
Slide96Object Snap
96
Polar Tracking
Polar tracking
works similar to ORTHO but has a wider range of angle options.
ORTHO forces cursor movement to
horizontal
or
vertical
only.
Polar angles can be selected by user.
The cursor snaps to preset incremental angles when a point is being located.
Slide97Polar Tracking
ORTHO and Polar Tracking cannot be used at the same time. AutoCAD automatically turns Ortho off when polar tracking is on, and it turns polar tracking off when Ortho is on.
Object Snap
97
Slide98Object Snap
98
Slide99Polar Tracking
Turn polar tracking on or off.1. Select the POLAR button from the status bar 2. Use the [F10] function key.
Object Snap
99
Slide100Polar Tracking
When polar tracking mode is turned on, the crosshairs snaps to preset incremental angles if a point is being located relative to another point. For example, in the LINE command, polar tracking is not active for the first endpoint selection, but it is available for the second and subsequent point selections.
Polar tracking vectors are displayed as dashed lines whenever the crosshairs aligns with any of these preset angles
Object Snap
100
Slide101Object Snap
101
Slide102Object Snap
102
Slide103Object Snap
103
Slide104Polar Tracking Overrides
Using polar tracking overridesAllows polar tracking for only one pointWorks for the specified angle whether polar tracking is on or off.
To activate a polar tracking override, type a left angle bracket (<) followed by the desired angle when AutoCAD asks you to specify a point.
Object Snap
104
Slide105Polar Tracking Overrides
The following command sequence uses a 30° override to draw a line 1.5 units long:Command: L or LINESpecify first point: (pick a start point for the line)
Specify next point or [Undo]: <30Angle Override: 30Specify next point or [Undo]: (move the crosshairs in the desired 30° direction) 1.5
Specify next point or [Undo]:
Command:
Object Snap
105
Slide106Temporary Tracking
Temporary Tracking vs Object SnapObject snap tracking has two requirements:
running object snap mode must be active and the crosshairs must pause over the selected point long enough to acquire it.Temporary track point can produce tracking vectors without either of these conditions.
Object Snap
106
Slide107Temporary Tracking
To activate temporary tracking, 1. pick the Temporary track point button from the Object Snap toolbar2. type TT at the selection prompt
3. pick Temporary track point from the Object Snap shortcut menu.
Object Snap
107
Slide108Temporary Tracking
Example: temporary tracking can be used to place a circle at the center of a rectangle. The X coordinate of the rectangle's center corresponds to the midpoint of the horizontal lines.
The Y coordinate of the rectangle's center corresponds to the midpoint of the vertical lines. Temporary tracking can be used to combine these two points to find the center of the rectangle
Object Snap
108
Slide109Temporary Tracking Example
Object Snap
109
Slide110From Point Selection Option
The From point selection option Another tracking tool Can be used to locate points based on existing geometry.
It allows you to establish A relative coordinateA polar coordinate, or
A direct distance entry from a specified reference base point.
Object Snap
110
Slide111From Point Selection Option
Access the From option by 1. selecting the Snap From button in the Object Snap toolbar2. selecting From in the Object Snap shortcut menu
3. typing FRO at a point selection prompt.
Object Snap
111
Slide112From Point Selection Option Example
Example shows the center point for a circle being established as a polar distance from the midpoint of an existing line.
Object Snap
112
Slide113From Point Selection Option Example
Object Snap
113
Slide114From Point Selection Option Example
The command sequence is shown here:Command: C or CIRCLESpecify center point for circle or [3P/2P/
Ttr (tan tan radius)]: FRO
Base point: MID
of (pick line)
<Offset>: @2<45
Specify radius of circle or [Diameter] <current>: (pick a radius)
Command
Object Snap
114
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