Compile Mask

Now reading version 20.2. For the latest, read: Compile Mask for version 21
Parent page: Schematic Objects

A placed Compile Mask, shown on the left side of the above schematic.A placed Compile Mask, shown on the left side of the above schematic.


A Compile Mask is a design directive that is used to effectively hide the area of the design it contains from the Compiler, when performing validation using the Project » Validate Project command. It provides a way to manually prevent error checking for circuitry that may not yet be complete and will generate validation errors. The Compile Mask is useful in circumstances where the current project needs to be validated to check the integrity of the design in other specific areas, but the clutter of compiler-generated messages associated with unfinished portions of the design is not desired.

Although called a 'Compile Mask', this directive is not associated with the act of compilation - which is automatically performed after each user operation, courtesy of Altium Designer's Dynamic Compilation feature. Rather, the Compile Mask comes into play when you manually run a validation of the project, which is separate and distinct to compilation, and a process that requires to be manually instigated by the user. Validation then checks the schematic documents within the project for electrical and drafting errors, in conjunction with settings defined on the Error Reporting and Connection Matrix tabs of the Project Options dialog.


Compile Masks are available for placement in the Schematic Editor only. To place a Compile Mask:

  • Click the Place » Directives » Compile Mask command from the main menus.
  • Click the Compile Mask button () in the directives drop down on the Active Bar located at the top of the workspace. Click and hold an Active Bar button to access other related commands. Once a command has been used, it will become the topmost item on that section of the Active Bar.
  • Right-click in the schematic editor then click Place » Directives » Compile Mask.


After launching the command, the cursor will change to a cross-hair indicating Compile Mask placement mode. Placement is made by performing the following sequence of actions:

  1. Position the cursor then click or press Enter to anchor the first corner of the mask.
  2. Move the cursor to adjust the size of the mask so that it completely encapsulates the area of the design that needs to be hidden from the Compiler, then click or press Enter to anchor the diagonally-opposite corner and complete placement of the mask. Design objects falling completely within the bounds of the mask will become grayed-out.
  3. Continue placing further compile masks or right-click or press Esc to exit placement mode.

Graphical Editing

This method of editing allows you to select a placed compile mask object directly in the workspace and change its size, shape or location graphically.

A compile mask can be displayed in either active (full frame) or collapsed (boxed triangle) modes, which correspond to the mask being enabled and disabled, respectively. Toggle the display mode by clicking on the or icon in the top-left corner of a placed compile mask.

Click the triangle in the top-left corner to collapse (and disable) a compile mask.Click the triangle in the top-left corner to collapse (and disable) a compile mask.

When an active (expanded) compile mask object is selected, the following editing handles are available:

A selected Compile Mask (when active).A selected Compile Mask (when active).

  • Click and drag A to resize the compile mask in the vertical and horizontal directions simultaneously.
  • Click and drag B to resize the compile mask in the vertical and horizontal directions separately.
  • Click anywhere on the compile mask – away from editing handles – and drag to reposition it. While dragging, the compile mask can be rotated (Spacebar/Shift+Spacebar) or mirrored (X or Y keys to mirror along the X-axis or Y-axis, respectively).
Note that when a Compile Mask is in its collapsed state, only its position may be graphically changed by dragging it to a new location.
If attempting to graphically modify an object that has its Locked property enabled, a dialog will appear asking for confirmation to proceed with the edit. If the Protect Locked Objects option is enabled on the Schematic – Graphical Editing page of the Preferences dialog, and the Locked option for that design object is enabled as well, then that object cannot be selected or graphically edited. Click the locked object to select it then disable the Locked property in the List panel or disable the Protect Locked Objects option to graphically edit the object.

Non-Graphical Editing

The following methods of non-graphical editing are available:

Via the Compile Mask Dialog or Properties Panel

Panel page: Compile Mask Properties

This method of editing uses the associated Compile Mask dialog and the Properties panel mode to modify the properties of a Compile Mask object.


After placement, the Compile Mask dialog can be accessed by:

  • Double-clicking on the placed compile mask object.
  • Selecting the compile mask object, right-clicking, then choosing Properties from the context menu.

During placement, the Compile Mask mode of the Properties panel can be accessed by pressing the Tab key. Once the compile mask is placed, all options appear.

After placement, the Compile Mask mode of the Properties panel can be accessed in one of the following ways:

  • If the Properties panel is already active, by selecting the compile mask object.
  • After selecting the compile mask object, select the Properties panel from the Panels button in the bottom right section of the workspace, or by selecting View » Panels » Properties from the main menu.
If the Double Click Runs Interactive Properties option is disabled (default) on the Schematic - Graphical Editing page of the Preferences dialog, when the primitive is double-clicked or you right-click on a selected primitive then choose Properties, the dialog will open. When the Double Click Runs Interactive Properties option is enabled, the Properties panel will open. 
While the options are the same in the dialog and the panel, the order and placement of the options may differ slightly. 

Editing Multiple objects

The Properties panel supports multiple object editing, where the property settings that are identical in all currently selected objects may be modified. When multiples of the same object type are selected manually, via the Find Similar Objects dialog or through a Filter or List panel, a Properties panel field entry that is not shown as an asterisk (*) may be edited for all selected objects.

Via the SCH List Panel

Panel pages: SCH List, SCH Filter

List panel displays design object types from one or more documents in tabular format, enabling quick inspection and modification of object attributes.

Used in conjunction with appropriate filtering – by selecting object types (using the panel's Include options), or by using the applicable Filter panel or the Find Similar Objects dialog – it enables the display of just those objects falling under the scope of the active filter. The properties for the listed objects may then be edited directly in the List panel.

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