Align Objects

Align Objects moves one object (the MOVING object) so that its points match points on another object (the DESTINATION object). Use it to line up a second layer, a drilled file, or a re-exported file with a reference object.

Where to find it

• Menu: Plugins > Align Objects.
• Keyboard: Alt+A.
• The panel opens in a tab next to Project and Properties. The tab shows the plugin name.

Quick start

1. Load the two objects. Both must be on the canvas.
2. Press Alt+A to open the tool.
3. In MOVING object, select the object type (Gerber, Excellon or Geometry). Select the object to move in the combo box below it.
4. In DESTINATION object, select the type and the reference object.
5. Keep Alignment Type at 1 Point or 2 Points.
6. Click Align Object.
7. On the canvas, click a START point on the moving object. Then click the matching DESTINATION point on the reference object.
8. The object moves when the pair is complete. The Points table shows the pair and the Error value.

Screenshot placeholder: images/Align-Objects-1.png — the tool panel with the MOVING and DESTINATION frames, the Parameters frame and the Points table.

Parameters

Tool header

Parameter	Description	Default
Beginner / Advanced (toggle button, top left)	Beginner hides Limit pairs. Advanced shows it. The choice here is for this session. The permanent choice is in Preferences.	Beginner

MOVING object

Parameter	Description	Default
Gerber / Excellon / Geometry (radio)	The object type of the moving object. It filters the object combo box.	Gerber
Object combo box (no label)	The object that is moved. Its list follows the type radio.	—

DESTINATION object

Parameter	Description	Default
Gerber / Excellon / Geometry (radio)	The object type of the reference object. It filters the object combo box.	Gerber
Object combo box (no label)	The reference object. The points on it are the DESTINATION points.	—

Parameters

Parameter	Description	Default
Alignment Type	Sets how the points are used. See the list below.	1 Point
Fit Model	The transformation fitted to the point pairs. Visible in Best Fit and Auto only. See the list below.	Rigid
Allow mirror	Auto mode only. Also tests a mirrored object. Use it for a layer of the bottom side.	Off
Limit pairs (checkbox)	Advanced mode only. Limits the source landmarks and the fitted pairs in Auto mode. Clear it for no limit.	Off
Limit pairs value (spin box)	The limit when Limit pairs is on. Zero means unlimited. Range 0 to 1000000.	6

Alignment Type (combo values are radio buttons):

• 1 Point: One START and one DESTINATION point. The object moves by a translation.
• 2 Points: Two pairs. The object moves by a translation, then a rotation.
• 2 Points + Scale: Two pairs. The object moves by a translation, a rotation and a uniform scale.
• Best Fit: Any number of pairs (at least 2). The fit model sets the transformation. Click Apply or press Enter to apply.
• Auto: The tool searches the alignment by itself. It matches the centers of the holes and pads of both objects. It shows up to 5 candidates.

Fit Model (combo values):

• Rigid: Translation and rotation. Needs 2 or more pairs.
• Similarity: Rigid plus a uniform scale. Needs 2 or more pairs.
• Affine: Rigid plus X/Y scale and skew. Needs 3 or more pairs, not all on one line.
• In Auto mode the fit model is used for the final refine.

Points

Parameter	Description	Default
Points table	Lists each pair: #, START X, START Y, DEST X, DEST Y and Error. Error is the distance between the moved START point and the DESTINATION point after the alignment. The table is read only.	—
Result label	Shows the result of the last search or alignment.	—

Buttons

Button	Description	Default
Align Object	Starts the point picking in 1 Point, 2 Points and 2 Points + Scale modes. Hidden in Auto mode.	—
Find	Auto mode only. Starts the automatic search.	—
Next candidate	Auto mode only. Shows the next best candidate. Disabled until a search finds one.	Disabled
Apply	Best Fit mode: fits the points and aligns the object. Auto mode: applies the shown candidate. Disabled until enough pairs exist.	Disabled
Reset Tool	Resets the tool fields and clears the points.	—

Advanced

• Point picking. A click snaps to the target object. The tool picks the smallest feature center under the click. If none is under the click, it picks the nearest vertex within 10 screen pixels. If nothing is within reach, it shows a warning and adds no point.
• Keys during picking. Backspace removes the last point. Enter applies in Best Fit mode. Esc or a right click cancels.
• Single application. The matrix is solved from the complete pairs and applied once. A solver error keeps the points. You can then add or remove a point.
• Auto mode. Auto needs holes or pads in both objects. The search runs in a background worker and shows a progress value. If the search fails, the tool shows an error.
• Undo. The move is recorded in the undo history as Align Objects.
• Tcl. There is no Tcl command for this tool. The Tcl commands aligndrill and aligndrillgrid are a different feature. See Tcl Command Reference.

See also

• Object Operations — transform, origin and other object edits.
• Transform — move, scale and rotate by values.
• Move — move an object by picking points.
• Distance — measure the distance between two points.
• Tcl Command Reference