How to Create a Mask in AutoCAD?

Creating a mask in AutoCAD involves using wipeout objects, or mask block definitions. Here's how to do it using each method:

1. Using Wipeout Objects (The Simplest Method)

The easiest way to create a mask is using the WIPEOUT command. This essentially creates a filled area that obscures underlying objects.

Steps:

1. Start the Wipeout Command: Type WIPEOUT in the command line and press Enter.
2. Specify the First Point: Click to specify the first corner of the area you want to mask.
3. Specify Subsequent Points: Continue clicking to define the boundary of the wipeout area. You can create rectangular or polygonal wipeouts.
4. Close the Wipeout: When finished defining the shape, type C in the command line and press Enter to close the wipeout.

Considerations for Wipeout Objects:

• Frame: Wipeout objects have a frame that is visible by default. To hide the frame, type WIPEOUT in the command line, then type F and press Enter. Choose OFF to hide the frame.
• Draw Order: Wipeout objects need to be drawn in the correct order to function as intended. Use the DRAWORDER command to bring the wipeout to the front or send it to the back. For example, to send a wipeout to the back:
  • Type DRAWORDER in the command line and press Enter.
  • Select the wipeout object.
  • Type B and press Enter to send it to the back.

2. Using Mask Block Definitions

This method is more advanced and typically used within custom blocks.

Steps:

1. Open Style Manager: Click the "Manage" tab, then the "Style & Display" panel, and select "Style Manager". Alternatively, type STYLEMANAGER in the command line.
2. Navigate to Mask Block Definitions: In the Style Manager, expand "Multi-Purpose Objects," then right-click "Mask Block Definitions," and click "New."
3. Name the Mask Block Definition: Enter a name for the new mask block definition and press Enter.
4. Set the Definition Source: Right-click the new mask block definition name and click "Set From." This allows you to select an existing object (like a closed polyline) that will define the shape of the mask.
5. Select the Object: Select the object you want to use as the basis for your mask. This object will determine the shape of the mask.
6. Insert the Block: You can now insert this mask block definition like any other block. When inserted, it will mask the underlying objects within the defined shape.

Use Cases for Mask Block Definitions:

• Title Blocks: To mask areas of the drawing that should be covered by the title block.
• Custom Symbols: Incorporating masking into custom symbols or blocks.
• Architectural Elements: Masking portions of architectural drawings.

Important Notes:

• Mask block definitions can provide a more integrated and automated masking solution when used within blocks.
• The wipeout object offers a quicker and simpler solution for basic masking needs.
• Always consider the draw order to ensure the masking effect works as expected.