Object snaps

Toolbar	Menu
Object Snap	Tools Object Snap > The menu versions turn the object snaps on for one pick only. For persistent object snaps, use the Osnap control.

Toolbar

Toolbar: Object Snap | Standard

Tools

Object Snap >

The menu versions turn the object snaps on for one pick only.
For persistent object snaps, use the Osnap control.

The object snaps constrain the marker to an exact location on an object such as the end of a line or the center of a circle.

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 control.
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

More than one object snap can be active at the same time. As the cursor passes 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, Tan, and Vertex 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 control

On the Rhino application menu, click Preferences...
In Rhino Preferences, click Themes.
Enable Include Osnaps panel in command sidbar under Modeling commands sidebar.
Select or clear the desired object snap check boxes.

To turn off all persistent object snaps

Enable Disable all.

Disabling the object snaps suspends their use temporarily.

When the Disable all check box is cleared, all previously set object snaps turn back on.

To enable only one object snap

Alt + click an object snap.

The object snap is enabled and all the others are disabled.

To temporarily suspend object snaps

Press Alt when a command prompts to pick a point.

When Disable all is on, checked object snaps are enabled temporarily.

When Disable all is off, checked object snaps are disabled temporarily.

One-shot object snaps

One-shot object snaps only work when Rhino is requesting a point, are turned on for one pick only, and override all persistent object snaps for that pick.

To set a one-shot object snap

Select One shot and click an object snap check box.

For example, if End, Near, and Point persistent object snaps are set in the Osnap control, 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.

Object snaps when dragging

When object snaps are on, click and hold near object snap locations to use them for the start or end locations of the drag.

To suspend object snaps for the drag, press and hold Alt.

Drag line from midpoint to circle center.

Project object snaps

The Project button on the Osnap control projects any object snap to the current construction plane. For example, in the illustration, the curve projects to the construction plane from snapped locations on an object.

See: ProjectOsnap

Object snap culling

Object snaps work on visible objects only by default. Objects that are obscured by other objects cannot be snapped.

When the cursor passes behind the red box, the object snap turns off.

Simple object snaps

Simple object snaps snap to one location on an object.

Steps

Move the cursor near the target object.
When the marker jumps to the snap location, click the left mouse button.

NoSnap

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

Center (Cen)

Snaps to the center of:

The average coordinates of the corners of a closed planar polyline.
The center point of an exact or approximate circle, ellipse, or arc.
A single surface, or a polysurface face with a boundary of (1) or (2) above. (No holes)
The bounding box of an annotation text.
The average coordinates of all the control points of a planar SubD.

See: Modeling Aids Options.

End

Snap to the end of a curve, text corners, interior vertices of polylines and joined curves, the seam point on closed curves, and the "corners" of surfaces, and polysurfaces.

Intersection (Int)

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

To isoparametric curves, use the OnSurface or OnPOlySurface object snap first.

To snap to mesh wires, the SnapToMeshes command has to be enabled.

Knot

Snap to a knot on a curve or surface.

Midpoint (Mid)

Snap to the midpoint of a curve, surface edge, mesh wire, polycurve segment, SubD edge or adjacent smart points.

If you place four smart points, A, B, C and D, only the midpoints between A and B, B and C, or C and D can be snapped.

To snap to mesh wires, the SnapToMeshes command has to be enabled.

Near

Snap onto a curve, mesh wire, surface edge or SubD edge at the cursor location.

To snap to mesh wires, the SnapToMeshes command has to be enabled.

Perpendicular (Perp)

Snap perpendicular to a curve, mesh wire, or surface edge.

The Perpendicular object snap is not effective for the first point of a command.

To snap to mesh wires, the SnapToMeshes command has to be enabled.

Point

Snap to a point object, extrusion point, control point, edit point, block, and text insertion points.

Also snaps to centers and corners of rectangular lights and block insertion points even if control points are not displayed.

Quadrant (Quad)

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

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.

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

Wikipedia: Tangent

Vertex

Snap to a mesh or SubD vertex.

Note

Use the CullControlPolygon to disable snapping to vertices on the back side of mesh objects.
Mesh vertices do not have to be turned on when using the Vertex snap.

Object snaps using references

When picking points during these steps, use simple snaps (End, Near, Point, Midpoint, Center, Intersection, and Quadrant) for greater precision.

To access reference object snaps from the Osnap control

Select One shot on the Osnap control.
The alternate reference object snaps appear.

Along

Track along a line.

Along example

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

Along steps

Pick the start of the tracking line (the center of the circle).
Pick the end of the tracking line (the end of the line).
The marker moves only along the tracking line.
Click the left mouse button to specify the location.

To access this object snap on the Osnap control

Select One shot on the Osnap control.

AlongParallel (AlongP)

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

AlongParallel example

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

AlongParallel steps

Pick the start of the base line (the corner of the box).
Pick the end of the base line (the other corner of the box).
Pick the start point for parallel tracking (the Center of the circle).
The marker moves only along the tracking line.
Click the left mouse button to specify the location for the start of the line.

To access this object snap on the Osnap control

Select One shot on the Osnap control.

Between

Snap midway between two specified locations.

Between example

Center a circle between two rectangles

Between steps

Pick the first reference point.
Pick the second reference point.

To access this object snap on the Osnap control

Select One shot on the Osnap control.

From

Snap from a specified base point.

Note

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.

From example

Center a circle four units from the endpoint of a line.

From steps

Snap the base point to the end of the line.
Type 4 and press Enter.
The marker is constrained to four units from the endpoint of the line.
Click to place the circle's Center point and pick the radius.

To access this object snap on the Osnap control

Select One shot on the Osnap control.

PerpendicularFrom (PerpFrom)

Track along a line perpendicular to a curve or surface.

PerpendicularFrom example

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

PerpendicularFrom steps

Select the curve.
The cursor moves only along the curve. Cross-hairs appear to indicate the perpendicular and tangent lines that extend from any point on the curve.
Pick the point on the curve to extend the perpendicular line from.
The marker tracks along the perpendicular line.
Click the left mouse button to start the line.

To access this object snap on the Osnap control

Select One shot on the Osnap control.

TangentFrom (TanFrom)

Track along a line tangent to a curve.

Wikipedia: Tangent

TangentFrom example

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

TangentFrom steps

Select the circle.
The marker moves only along the circle. Cross-hairs indicate the perpendicular and tangent lines that extend from any point on the circle.
Pick the point on the circle to extend the tangent line from.
The marker tracks along on the tangent line.
Click the left mouse button to start the line.

To access this object snap on the Osnap control

Select One shot on the Osnap control.

Object snaps on an object

OnCurve (OnCrv)

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

Notes

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 curve parameter displays in the status bar when moving the mouse along the curve.

OnCurve example

Select the curve to move a control point along.

OnCurve steps

Select the curve.
The marker moves only along the selected curve.
Click the left mouse button to place the point.

To access this object snap on the Osnap control

Select One shot on the Osnap control.

PersistentOnCurve (POnCrv)

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

To access this object snap on the Osnap control

Select the One shot on the Osnap control.

OnPolysurface (OnPSrf)

Snap to and track over a polysurface for one pick.

OnPolysurface example

Place a point object on a polysurface.

OnPolysurface steps

Select the polysurface.
The marker moves only over the polysurface.
Click the left mouse button to place the points.

To access this object snap on the Osnap control

Select One shot on the Osnap control.

PersistentOnPolysurface (POnPSrf)

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

To access this object snap on the Osnap control

Select the One shot on the Osnap control.

OnMesh

Snap to and track along a selected mesh object for one pick.

OnMesh steps

Select the mesh.
The marker moves only along the selected mesh.
Click the left mouse button to place the point.

To access this object snap on the Osnap control

Select the One shot on the Osnap control.

PersistentOnMesh (POnMesh)

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

To access this object snap on the Osnap control

Select the One shot on the Osnap control.

OnSurface (OnSrf)

Snap to and track over a surface for one pick.

OnSurface example

Place a point object on a surface.

OnSurface steps

Select the surface.
The marker moves only over the surface.
Click the left mouse button to place the point.
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.

To access this object snap on the Osnap control

Select One shot on the Osnap control.

PersistentOnSurface (POnSrf)

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

To access this object snap on the Osnap control

Select the One shot on the Osnap control.

Percentage (Percent)

The selected curve is marked with temporary black points that can be snapped when the Point object snap is disabled.

If the percentage is less than 50, the curve is marked with multiple snap points. For example, when using 30, you get snap points at 30%, 60% and 90%.

To access this object snap on the Osnap control

Select the One shot on the Osnap control.

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 curves 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.

Related commands

Osnap

Toolbar	Menu	Status bar
Osnap	Tools Object Snap > <Options>	Osnap

Toolbar

Status bar

Toolbar: Object Snap

Osnap

Tools

Object Snap >

Osnap

The Osnap command sets the status of object snaps from the command line.

Steps

Specify a command line option.

Note

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.

ShowOsnap

Toolbar	Menu
Object Snap Standard	Tools Object Snap > Persistent Osnap Dialog

Toolbar

Toolbar: Object Snap | Standard

Object Snap
Standard

Tools

Object Snap >

Persistent Osnap Dialog

The ShowOsnap command turns the floating Osnap control on, off, or toggles the current state.

Steps

Specify a command line option.

Command-line options
Show	Turns the floating Osnap control on.
Hide	Turns the floating Osnap control off.
Toggle	Toggles the floating Osnap control.

DisableOsnap

Toolbar	Menu
Object Snap	Tools Object Snap > Disable Object Snaps

Toolbar

Toolbar: Object Snap

Object Snap

Tools

Object Snap >

Disable Object Snaps

The DisableOsnap command manages the state of persistent object snaps.

To temporarily turn off persistent object snaps from the control

In the Osnap control, select the Disable all check box.
When Object snaps are disabled, persistent object snaps are temporarily suspended.

To reactivate persistent object snaps from the control

In the Osnap control, clear the Disable all check box.
All persistent object snaps will be reactivated.

To temporarily turn off persistent object snaps from the command line

Click an option.

ProjectOsnap

Toolbar	Menu
Object Snap	Tools Object Snap > Project to Plane

Toolbar

Toolbar: Object Snap

Object Snap

Tools

Object Snap >

Project to Plane

The ProjectOsnap command projects object snaps from the actual snap point to the construction plane.

Steps

Specify a command line 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.
When projection is on, the prefix "Projected" is added to the tooltip as a reminder.

Command-line options
Enable	Object snaps will be projected to the construction plane.
Disable	Object snaps land on the object snapped to.
Toggle

SnapToLocked

Toolbar	Menu
Object Snap	Tools Object Snap > Snap To Locked Objects

Toolbar

Toolbar: Object Snap

Object Snap

Tools

Object Snap >

Snap To Locked Objects

The SnapToLocked command snaps work on locked objects and on objects on locked layers.

SnapToMeshes

Toolbar	Menu	Preferences
Not on toolbars.	Not on menus.	Modeling Aids > Snaps Near, Mid, Int and Perp snap to mesh objects

Toolbar

Preferences

Not on toolbars.

Not on menus.

Modeling Aids > Snaps

Near, Mid, Int and Perp snap to mesh objects

The SnapToMeshes command enables/disables snapping to mesh edges using Near, Mid, Int, and Perp object snaps.

SnapToOccluded

Toolbar	Menu
Not on toolbars.	Not on menus.

Toolbar

Not on toolbars.

Not on menus.

The SnapToOccluded command allows object snaps to work on objects that are hidden behind other objects.

ToggleOsnapPanel

Toolbar	Menu
Not on toolbars.	Not on menus.

Toolbar

Not on toolbars.

Not on menus.

The ToggleOsnapPanel command turns the display of the floating Object Snaps panel on and off.

ToggleOsnapPanelUnderCursor

Toolbar	Menu
Not on toolbars.	Not on menus.

Toolbar

Not on toolbars.

Not on menus.

The ToggleOsnapPanelUnderCursor shows or hides the Object Snaps in a floating panel and always places it under the cursor.

When you use this command, the Object Snaps panel also will disappear as soon as you move the cursor off the Object Snaps panel.

This command is intended to be used as a macro assigned to a mouse button if you have a mouse with more than three buttons or to a trackpad swipe gesture.