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Object Snaps, Grid Snap, and Ortho Mode ​

Snapping constrains the cursor to geometrically significant points and directions, making it possible to draw accurately without typing exact coordinates for every point.

Object Snap Modes ​

Object snaps (OSnaps) lock the cursor to specific points on existing entities when the cursor comes within the snap threshold (15 screen pixels by default). The active snap type is shown by a colored marker on the canvas.

PlanCAD provides eight object snap types:

Endpoint ​

Snaps to the start or end point of lines, polyline segments, arcs, and splines. This is the most frequently used snap and has the highest priority in the snap engine.

Midpoint ​

Snaps to the geometric midpoint of line segments, polyline segments, and arcs.

Center ​

Snaps to the center of circles, arcs, and ellipses.

Perpendicular ​

Snaps to the point on a line or segment that forms a 90-degree angle with the previous point you picked. Useful for drawing lines that are perpendicular to an existing edge.

Intersection ​

Snaps to the point where two entities cross. Intersection snap is computationally more expensive than other modes and is only evaluated when the zoom level is above a minimum threshold. It is skipped automatically on very dense or zoomed-out drawings to maintain performance.

Quadrant ​

Snaps to the four cardinal points of a circle or arc (0 deg, 90 deg, 180 deg, 270 deg relative to center).

Tangent ​

Snaps to the tangent point on a circle or arc from the previous picked point. Use this when connecting a line to a circle so that the line touches the circle without crossing it.

Nearest ​

Snaps to the closest point on any visible entity segment. Nearest has the lowest priority and only activates when no higher-priority snap is found. It ensures the cursor always lands on geometry when close to it.

Snap Priority ​

When multiple snap types could apply simultaneously, the engine selects the closest match in the following priority order:

  1. Endpoint, Midpoint, Center, Quadrant (evaluated together via spatial index — fastest)
  2. Perpendicular
  3. Tangent
  4. Intersection
  5. Nearest
  6. Grid (only if no entity snap was found)

Enabling and Disabling Individual Snap Types ​

Click the Snap button in the toolbar to toggle the snap system on or off globally. Right-click the Snap button to open the Snap Settings popup.

The popup lists all eight snap types with checkboxes:

  • Endpoint
  • Midpoint
  • Center
  • Perpendicular
  • Intersection
  • Quadrant
  • Tangent
  • Nearest

Uncheck any type to disable it. For example, disabling Nearest prevents the cursor from sticking to arbitrary points along segments when you only want to snap to key geometry.

Snap settings persist across sessions.

Grid Snap ​

Grid snap constrains the cursor to a regular grid of points in model space. It is independent of object snaps: both can be active at the same time, and object snap takes priority over grid snap when an entity snap is found.

Adaptive Grid Size ​

The grid interval adapts automatically to the current zoom level. The engine targets a visual spacing of 10–100 pixels on screen, halving or doubling the interval as you zoom in or out:

  • Zoomed out: the grid coarsens so that lines do not crowd the display.
  • Zoomed in: the grid refines for fine placement.

The minimum grid interval is 0.1 drawing unit. Grid lines are rendered on the canvas to match the current snap interval.

Toggling Grid Snap ​

Click the Snap button in the toolbar (the # icon) to toggle grid snap. The button is highlighted when grid snap is active. The status bar shows SNAP in green when enabled.

Ortho Mode ​

Ortho mode restricts cursor movement to exactly horizontal or vertical relative to the last picked point. When active, you can only draw at 0, 90, 180, or 270 degrees.

Activating Ortho Mode ​

  • Press F8 at any time to toggle ortho on or off.
  • Click the ORTHO button in the toolbar.

The status bar displays ORTHO in green when it is active.

How It Works ​

While ortho is active, as you move the cursor after picking a first point, PlanCAD compares the horizontal and vertical distance from the anchor:

  • If the horizontal distance is greater, the cursor locks to the horizontal axis.
  • If the vertical distance is greater, the cursor locks to the vertical axis.

The locked point is used as the next input coordinate. Typed distances (see below) are applied along the constrained axis direction.

Ortho mode and object snaps work together: the cursor snaps to the nearest endpoint or midpoint along the constrained axis.

Polar Tracking ​

Polar tracking extends ortho to any angular increment, not just 90-degree steps. When enabled, the cursor snaps to the nearest multiple of the configured angle as you move away from the last point.

Activating Polar Tracking ​

  • Press F10 to toggle polar tracking.
  • Click the POLAR button in the toolbar.

When active, the status bar shows POLAR N° where N is the current angle increment (e.g., POLAR 45°).

Configuring the Angle Increment ​

In the toolbar secondary bar, a numeric input next to the POLAR button sets the angle increment in degrees. Common values: 15, 30, 45, 90. For example, with 30-degree increments the cursor snaps to 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, and 330 degrees.

The angle is measured from the positive X axis (East), counter-clockwise.

Polar tracking and ortho mode are independent. Ortho overrides polar tracking when both are active, since ortho is a strict 90-degree constraint.

Typed Coordinates Bypass Snap ​

If you type a coordinate or distance while a tool is active, snap is bypassed entirely and the exact typed value is used. For example:

  • Type 1500 and press Enter while the Line tool is waiting for the second point to place it exactly 1500 units away in the current direction.
  • Type 100,200 to specify an absolute X,Y coordinate.

This lets you combine snapping for approximate placement with typed entry for precise values, depending on what is faster for each point.

Snap Indicators on Canvas ​

When a snap locks the cursor, a small colored marker appears at the snap point:

  • Square — grid snap
  • Triangle or X — endpoint / midpoint
  • Circle — center
  • Perpendicular symbol — perpendicular
  • Cross — intersection
  • Diamond — quadrant / nearest / tangent

The marker color matches the snap type. Moving the cursor away releases the snap lock until a new snap point is found.