Object snaps

Object snaps constrain the marker

to an exact location on an object such as the center of a circle or the midpoint of a line.

See Also: SmartTrack …

When Rhino asks you to choose a point, you can constrain the marker

to specific parts of existing objects by turning on object snap modes. When an object snap is active, moving the cursor near a specified point on an object causes the marker

to jump to that point.

Object snaps can persist from pick to pick, or can be activated for one pick only. Multiple persistent object snaps can be set in the Osnap dialog box. All object snaps behave similarly, but snap to different parts of existing geometry.

For example, the End object snap finds the endpoint of a curve. When activated, the end object snap constrains the marker

to the endpoint of the curve closest the cursor.

Multiple object snaps

You can have more than one object snap active at the same time. As you pass your cursor over an object, the appropriate object snap displays.

Persistent object snaps

Use persistent objects snaps to maintain an object snap through choosing several points without having to reactivate the object snap. Only Cen
, End
, Int
, Knot
, Mid
, Near
, Perp
, Point
, Quad
, and Tan
object snaps can persist.

You can set the Snap radius
for object snaps. This means how close you have to move the cursor to the point before the marker

jumps to the point.

To display the Osnap dialog box

  1. On the status bar, click Osnap.

  2. Rhinoceros Osnap 001 Object snaps

  3. Select or clear the desired object snap check boxes.

To turn off all persistent object snaps

  • Click Disable.

  • Note: Disabling the object snaps suspends their use temporarily. When the Disable checkbox is cleared, all previously set object snaps turn back on.

To clear all persistent object snaps

  1. Right-click Disable.

  2. Press the Alt

    key to temporarily suspend object snaps.

  3. If object snaps are locked, press the Alt

    key to toggle them on temporarily.

One-shot object snaps

One-shot object snaps only work when Rhino is requesting a point and are turned on for one pick

only. One-shot object snaps override all persistent object snaps for one pick

. For example, if End
, Near
, and Point
persistent object snaps are set in the Osnap dialog box, and you set the Mid
object snap for one pick

, End
, Near
, and Point
will not work for that pick

. After the pick

, the persistent object snaps will reactivate.

Simple object snaps

Steps:

  1. Move the cursor near the target object.

  2. When the marker

    jumps to the snap location, click the left mouse button

    .

Center (Cen)

Snap to the center of a circle, arc, or closed polyline.

Rhinoceros CenterSnap Object snaps

Object Snap > Center

Rhinoceros Menu2 Object snaps

Tools > Object Snap >Center

End

Snap to the end of a curve.

Note: The End object snap also snaps to interior vertices of polylines
and joined curves, the seam
point on closed curves, and the “corners” of surfaces.

Rhinoceros EndSnap Object snaps

Object Snap > End

Rhinoceros Menu2 Object snaps

Tools > Object Snap >End

Intersection (Int)

Snap to the intersections of curves, edges, and isoparametric curves
on a surface.

Rhinoceros IntersectionSnap Object snaps

Object Snap > Intersection

Rhinoceros Menu2 Object snaps

Tools > Object Snap >Intersection

Knot

Snap to a knot
on a curve or surface.

Rhinoceros KnotSnap Object snaps

Object Snap > Knot

Rhinoceros Menu2 Object snaps

Tools > Object Snap >Knot

MidPoint (Mid)

Snap to the midpoint of a curve

Rhinoceros MidpointSnap Object snaps

Object Snap > Midpoint

Rhinoceros Menu2 Object snaps

Tools > Object Snap > Midpoint

Near

Snap onto a curve at the cursor location.

Rhinoceros NearSnap Object snaps

Object Snap > Near

Rhinoceros Menu2 Object snaps

Tools > Object Snap > Near

NoSnap

If a command is active, NoSnap turns off persistent object snaps for one pick.

Rhinoceros nosnap Object snaps

Object Snap > No Osnap

Rhinoceros Menu2 Object snaps

Tools > Object Snap > None

Perpendicular (Perp)

Snap perpendicular to a curve.

Note: The Perp object snap is not effective for the first point for a command.

Rhinoceros perpendicular Object snaps

Object Snap > Perpendicular To

Rhinoceros Menu2 Object snaps

Tools > Object Snap > Perpendicular To

Point

Snap to a point object, control point
, edit point
, or mesh vertex
.

Rhinoceros pointsnap Object snaps

Object Snap > Point

Rhinoceros Menu2 Object snaps

Tools > Object Snap > Point

Quadrant (Quad)

Snap to the point on a curve that is at the maximum x or y point relative to the current construction plane.

Rhinoceros quadrantsnap Object snaps

Object Snap > Quadrant

Rhinoceros Menu2 Object snaps

Tools > Object Snap > Quadrant

Note:

  • The quadrant points of circles
    and arcs
    are at the extremes in each construction plane axis direction.

  • Ellipses
    have quadrant points at the ends of the ellipse axes if the ellipse is oblique in addition to those at the construction plane extremes.

Tangent (Tan)

Snap tangent to a curve.

Note: The Tan object snap is not effective for the first point for a command.

Rhinoceros tan Object snaps

Object Snap > Tangent To

Rhinoceros Menu2 Object snaps

Tools > Object Snap > Tangent To

Complex object snaps

Notes

  • These tools cannot be used in aliases
    .

  • When picking points during these steps, use simple snaps (End
    , Near
    , Point
    , Mid
    , Cen
    , Int
    , and Quad)
    for greater precision.

AlongLine

Track along a line.

Rhinoceros AlongLine Object snaps

Object Snap > Along Line

Rhinoceros Menu2 Object snaps

Tools > Object Snap > Along Line

Example:

Start a circle located on the line between the center of the circle and the end of a line.

  1. Pick

    the start of the tracking line (the center of the circle).

  2. Pick the end of the tracking line (the end of the line).

  3. The marker

    moves only along the tracking line

  4. Click the left mouse button

    to specify the location.

AlongParallel

Track along a line parallel to a reference line between two points.

Rhinoceros AlongParallel Object snaps

Object Snap > AlongParallel

Rhinoceros Menu2 Object snaps

Tools > Object Snap > Along Parallel

Example:

Start a line along a line parallel to the rectangle that passes through the circle’s center.

  1. Pick

    the start of the base line (the corner of the box).

  2. Pick the end of the base line

    (the other corner of the box).

  3. Pick the start point for parallel tracking (the center of the circle).

  4. The marker

    moves only along the tracking line.

  5. Click the left mouse button

    to specify the location for the start of the line.

Between

Snap midway between two specified locations.

Rhinoceros Between Object snaps

Object Snap > Between

Rhinoceros Menu2 Object snaps

Tools > Object Snap > Between

Example:

Center a circle between two rectangles

  1. Pick

    the first reference point.

  2. Pick the second reference point.

From

Snap from a specified base point

Rhinoceros From Object snaps

Object Snap > From

Rhinoceros Menu2 Object snaps

Tools > Object Snap > From

Notes

  • The From object snap differs from the rest of the object snap because it is used to set the base point for ortho
    , distance constraint
    , angle constraint
    , and relative coordinate entry
    .

  • Ortho
    constrains the marker

    to lines radiating from the last pick point. Similarly, distance constraint constrains the marker

    to a circle of a specified radius from the last pick point. You can set this point, without picking it, with the From object snap.

Example:

Center a circle four units from the endpoint of a line

  1. Snap the base point to the end of the line.

  2. Type 4 and press Enter

    .

  3. The marker

    is constrained to four units from the endpoint of the line.

  4. Click to place the circle’s center point and pick the radius.

OnCrv

Snap to and track along a selected curve for one pick.

Rhinoceros oncurve Object snaps

Object Snap > On Curve

Rhinoceros Menu2 Object snaps

Tools > Object Snap > On Object > On Curve

Note:

  • The OnCrv object snap is useful if the model is complex and Near object snap alone does not lock to the object you would like it to.

  • The Near
    object snap can allow the point to move to a different curve.

  • The OnCrv object snap lets you specify which curve.

Example:

Select the curve to move a control point along

  1. Select

    the curve.

  2. The marker

    moves only along the selected curve.

  3. Click the left mouse button

    to place the point.

PersistentOnCrv

Snap to and track along a selected curve until the command completes.

Rhinoceros PersistentOnCurve Object snaps

Object Snap > Persistent On Curve (Right click)

Rhinoceros Menu2 Object snaps

Tools > Object Snap > On Object > Persistent On Curve

OnSurface

Snap to and track over a surface for one pick.

Rhinoceros onsurface Object snaps

Object Snap > On Surface

Rhinoceros Menu2 Object snaps

Tools > Object Snap > On Object > On Surface

Example:

Place a point object on a surface.

  1. Select

    the surface.

  2. The marker

    moves only over the surface.

  3. Click the left mouse button

    to place the point.

  4. Note: If you are tracking over a polysurface, the marker is restricted to the single selected face. The cursor changes shape to indicate that you cannot pick. To track over the whole polysurface, see the OnPolysrf
    object snap.

PersistentOnSurface

Snap to and track over a surface until the command completes.

Rhinoceros PersistentOnSurface Object snaps

Object Snap > Persistent On Surface (Right click)

Rhinoceros Menu2 Object snaps

Tools > Object Snap > On Object > Persistent On Surface

OnPolysurface

Snap to and track over a polysurface for one pick.

Rhinoceros OnPolysurface Object snaps

Object Snap > On Polysurface

Rhinoceros Menu2 Object snaps

Tools > Object Snap > On Object > On Polysurface

Example:

Place a point object on a polysurface.

  1. Select

    the polysurface.

  2. The marker

    moves only over the polysurface.

  3. Click the left mouse button

    to place the points.

PersistentOnPolySrf

Snap to and track over a polysurface until the command completes.

Rhinoceros PersistentOnPolysurface Object snaps

Object Snap > Persistent On Polysurface (Right click)

Rhinoceros Menu2 Object snaps

Tools > Object Snap > On Object > Persistent On Polysurface

PerpendicularFrom

Track along a line perpendicular to a curve.

Rhinoceros Perpendicularfrom Object snaps

Object Snap > Perpendicular From

Rhinoceros Menu2 Object snaps

Tools > Object Snap > Perpendicular From

Example:

Draw a line perpendicular from a line at the intersection with the circle

  1. Select

    the curve.

  2. The cursor moves only along the curve. Crosshairs appear to indicate the perpendicular and tangent lines that extend from any point on the curve.

  3. Pick

    the point on the curve to extend the perpendicular line from.

  4. The marker

    tracks along the perpendicular line.

  5. Click the left mouse button

    to start the line.

TangentFrom

Track along a line tangent to a curve.

Rhinoceros TangentFrom Object snaps

Object Snap > Tangent From

Rhinoceros Menu2 Object snaps

Tools > Object Snap > Tangent From

Example:

Draw a line tangent from the circle at the intersection with the line.

  1. Select

    the circle.

  2. The marker

    moves only along the circle. Crosshairs indicate the perpendicular and tangent lines that extend from any point on the circle.

  3. Pick

    the point on the circle to extend the tangent line from.

  4. The marker

    tracks along on the tangent line.

  5. Click the left mouse button

    to start the line.

Isoparametric curve snapping

You can snap to surface isoparametric curves using the Int
object snap whenever the input is constrained to a surface, for example in ExtractIsocurve
, InsertKnot
, OrientOnSrf
, and with OnSrf
, and OnPolysrf
one-shot object snaps.

Isoparametric curve object snapping is “weaker” than normal object snaps. The normal object snaps are evaluated first, and only if they fail will Rhino try to snap to the isoparametric curve intersections.

Scripting one-shot object snaps

One-shot object snaps are automatically transparent. In other words, when scripting these, you do not need to use the apostrophe character to make the object snap work while a command is running.

Osnap

Sets the status of object snaps from the command line.

Steps:

  • Click an option.

Notes

  • This command is useful for scripting, because it can set any object snap combination from command line.

  • You can temporarily suspend the effect of the object snaps with the DisableOsnap
    command.

Rhinoceros  ABlankButton Object snaps

None

Rhinoceros Menu2 Object snaps

None

Rhinoceros Gray Book Open Object snaps Related topics…

DisableOsnap

Manages the state of persistent object snaps.

To temporarily turn off persistent object snaps from the dialog box

  • In the Osnap dialog box, click the Disable button.

  • When Object snaps are disabled, persistent object snaps are temporarily suspended.

    Rhinoceros disableosnap 001 Object snaps

To reactivate persistent object snaps from the dialog box

  • In the Osnap dialog box, deactivate the Disable button.

  • All persistent object snaps will be reactivated.

    Rhinoceros disableosnap 002 Object snaps

To clear all persistent object snaps from the dialog box

  • In the Osnap dialog box, right-click

    the Disable button.

To temporarily turn off persistent object snaps from the command line

  • Click an option.

Options

Enable

Disable

Toggle

Rhinoceros DisableOsnap Object snaps

Object Snap > Disable/Enable Object Snap

Rhinoceros Menu2 Object snaps

Tools > Object Snap > Disable Object Snaps

Rhinoceros Gray Book Open Object snaps Related topics…

ProjectOsnap

Projects object snaps from the actual snap point to the construction plane.

Steps:

  • Click an option.

When Osnap projection is on, and the cursor is over an object snap point, the marker

projects to the current construction plane with a white tracking line between it and the cursor.

If Planar
mode is on, the ProjectOsnap command will project the object snap to the “virtual plane” that is set by the planar mode.

Options

Enable

Disable

Toggle

Rhinoceros ProjectOsnap Object snaps

Object Snap > Toggle Project-to-CPlane

Rhinoceros Menu2 Object snaps

Tools > Object Snap > Project to Plane

Rhinoceros Gray Book Open Object snaps Related topics…

ShowOsnap

Turns the Osnap toolbar on, off, or toggles the current state.

Steps:

  • Click an option.

Options

Show

Hide

Toggle

Rhinoceros ShowOsnap Object snaps

Object Snap > Show Object Snap Toolbar

Rhinoceros Menu2 Object snaps

None

Rhinoceros Gray Book Open Object snaps Related topics…

 

Object snaps