Object Snaps

Object Snaps

Object snap (OSNAP) pulls the cursor onto exact features of existing geometry, so a picked point lands on a real endpoint or intersection instead of near it.

Turning snap on and off

Choosing which snaps are active

Right-click the OSNAP button on the status bar for a checklist, or open Settings → Drafting. Both edit the same eight toggles.

Geometric center and Apparent intersection ship off — if you want either, tick it first.

Two related settings live in Settings → Drafting: Aperture (screen px) (default 14.0), how near the cursor must be for a snap to be offered, and Snap indicator half-size (px) (default 15.0), the size of the glyph drawn at the candidate.

When two candidates are equally close, the higher-priority one wins. Grips of selected objects beat every geometry snap and work regardless of the OSNAP toggle; no glyph is drawn for them.

Intersection versus apparent intersection

This distinction matters as soon as a drawing has elevations.

• Intersection is a real crossing: the two objects meet in space. This is as precise a feature as an endpoint, and is ranked as such.
• Apparent intersection is a crossing in the current view only. Two lines at different elevations look like they cross in plan view; they do not touch. Where the two candidate points differ, the one nearer the camera is offered.

A plan view cannot distinguish the two. Orbit the model (ORBIT) and the difference becomes obvious. If you are working in 3D and want only genuine intersections, turn Apparent intersection off.

Perpendicular

Perpendicular only fires when the running command supplies a reference point to be perpendicular from — the previous LINE point, the circle centre while sizing a radius, an earlier 3-point pick, and so on. Without a reference there is nothing to be perpendicular to, and the snap offers nothing.

One-shot snap override

Shift + right-click in the viewport opens the Snap once — choose type menu.

1. Pick a snap type from the list. Only the types you have enabled appear, and Perpendicular appears only when the running command has a reference.
2. The menu then lists every snap of that type in the model, sorted by distance from where you clicked — not just the ones near the cursor.
3. Click one to use it for this single pick.

Back returns to the type list. If there are none, the menu says "No matching snaps in the current geometry."

This is how you reach a snap that is buried under other geometry, or one that is off screen.

Snapping to PDF underlays

Object snap also works on attached PDFs. Snap targets are found by analysing the rendered raster image rather than the internal PDF path structure, so snap fires at the geometry you can actually see.

Candidates are filtered through a visibility mask, so only points in areas with visible content are offered.

Each attachment has its own snap toggles — Lines, Circles, Text — on the PDF Underlay ribbon section and in the Properties panel. See PDF Underlays.

Why raster-based — GIS exports, scanned drawings, and other dense PDFs routinely contain internal path objects that do not correspond to visible line geometry. Reading the rendered image is what makes snap land on what you see.

Snap and the commands that ignore it

A few operations deliberately use the unsnapped cursor, because a nearby snap point would drag a corner off target:

• DELETE selection windows
• ZOOMWINDOW corners

Preview versus commit

Rubber-band previews follow the cursor; the pick commits at the snapped point. These are not always the same place — hover just inside the rim of a circle with Center enabled and the preview shows the rim while the commit takes the centre.

If a result lands somewhere unexpected, look at the snap glyph before you click: the glyph marks where the pick will actually go.

Common problems

Related

Coordinate Input · Drafting Aids · PDF Underlays · Object Selection