Autodesk 00128-051462-9310 User Guide - Page 1584

Mask Blocks A mask block is a two-dimensional (2D) block that covers, or "masks," part of the graphic display of an AEC object in a plan view. You can use mask blocks to clean up or correct objects in your drawings or to create custom 2D shapes from predefined drawing objects, such as walls or grids. For example, attach a light fixture as a mask block to a ceiling grid in a plan view. If the light fixture is bigger than one or more of the ceiling grid bays, the light fixture masks, or covers, the ceiling grid lines that would visibly pass through the light fixture if it had been defined as a regular AutoCAD block. Before you can begin to mask objects in your plan view drawings, you must have an existing mask block or a mask block definition created in your drawing. You can find predefined mask blocks on the Drafting tool palette and in the AutoCAD Architecture Stock Tool catalog. You can also create a mask block with the AEC Content Wizard. For more information about custom content, see "Creating an AEC Content Masking Block for DesignCenter" on page 2125. After you have selected a mask block, add it to your drawing in plan view. Adding the mask block to your drawing is like adding a regular AutoCAD block: specify an insertion point or scale factors and a rotation angle. The mask block and the object that you want to mask must be coplanar; that is, for the mask object to cover the other object, they must be on the same plane. After you insert a mask block in your drawing, attach the objects to be masked. The mask block clips the graphics of the objects that you are masking when the objects regenerate themselves in a plan view. Only the objects that you attach to the mask block are clipped. The masked objects are plotted as you see them on your screen. If you change your drawing from a 2D view to a three-dimensional (3D) view, the mask block is still displayed, but it no longer masks the objects that are attached to it. You can detach the mask block from the objects at any time. You can also import and export mask block definitions. If you create a mask block definition that you decide not to use in your drawings, you can purge it. Creating Mask Block Definitions You can define a mask block by selecting a closed polyline in the drawing and defining it as a mask block, by copying and editing an existing mask block, or by using the AEC Content Wizard. Use the AEC Content Wizard to save mask blocks in content drawings for convenient reuse. For more information, see "Creating an AEC Content Masking Block for DesignCenter" on page 2125. Managing Mask Block Definitions To create, edit, copy, or purge mask block definitions, use the Style Manager. The Style Manager provides a central location in AutoCAD Architecture, where you can work with definitions and styles from multiple drawings and templates. For more information, see "Style Manager" on page 490. Creating a Mask Block Definition from a Polyline Use this procedure to create a mask block definition from one or more closed polylines. If you use more than one polyline to create your mask block definition, the polylines must be completely within or completely outside each other: they cannot overlap or touch. Polylines that are within each other can be specified as void areas that become holes when the mask block is created. After you create the definition, edit the definition properties to customize the characteristics of the definition. 1 On the Format menu, click Style Manager. The Style Manager is displayed, with the current drawing expanded in the tree view. 2 Expand Multi-Purpose Objects, right-click Mask Block Definitions, and click New. 3 Enter a name for the new mask block definition, and press ENTER. 4 Right-click the new mask block definition name, and click Set From. 5 Select the closed polyline to use to create the mask block definition. 6 Do one of the following to complete the mask block definition: ■ Press ENTER to create the mask block definition from a single polyline. 1544 | Chapter 34 Mask Blocks