ACA Ceiling Grids: Mask Blocks

First post in the series: ACA Ceiling Grids: The Cell Component
Previous post in the series: ACA Ceiling Grids: Anchors

AutoCAD^® Architecture Ceiling Grids provide an easy way to generate a representation of the ceiling grid for an acoustical panel ceiling. And, as we have seen in previous articles in this series, they have feature that make it easy to locate and organize ceiling devices. There are occasions, such as when using 2x4 luminaires in a 2x2 ceiling grid,

where specific segments of the grid need to be removed. While you can certainly use linework to create a custom grid with just the grid segments you need, it can be tedious to update should design changes move things around. A Mask Block is an AEC object designed just for this situation - using one allows you to "hide" unwanted grid segments without the need for a custom grid, at the same time you are placing the the ceiling object that requires the removal of the grid segment.

In this article, we will make use of an out-of-the-box Mask Block to show how one is used. A future article will show how to create one.

The Design Tool Catalog - Imperial includes a 2x4 fluorescent luminaire Mask Block tool in Electrical > Lighting > Fluorescent, 2x4. For those using Metric units, the Design Tool Catalog - Metric has a 450x900 fluorescent luminaire Mask Block tool in Electrical Services > Fluorescent, 450x900. The images here were taken from the Imperial content. Using the tool to place the Mask Block results in what is seen in the image above. Select the Mask Block and, on the Mask Block Reference contextual ribbon tab, on the Modify panel, choose the Attach Objects tool.

At the Select AEC object to be masked prompt, choose the ceiling grid. In the Select Display Representation dialog, select the Display Representation(s) for which the object is to be masked.

The result can be seen in the image below.

You will only be offered the Display Representation(s) that is(are) turned on for the current Display Configuration and View Direction. If you need the mask to be applied to other Display Representations used by a different Display Configuration (for example, in addition to the Reflected Display Representation shown here, you may need to also apply the mask for the Reflected Screened Display Representation), you will need to change to a Display Configuration/View Direction that makes the other Display Representation active and repeat this process. If you routinely need to mask multiple Display Representations, you may want to create a "working" Display Configuration for reflected ceilings that has all of the various Display Representations for Ceiling Grids turned on, so you can mask all of them at once.

Anchors can also be applied to Mask Blocks, so you can use a node anchor to keep your 2x4 luminaire locked to a node of the grid, as discussed in the previous article. Since the insertion point for this Mask Block is at a grid point, no offset is required.

Note also that, unlike copies of anchored AEC objects, copies of the Mask Block will not inherit the mask. You can, however, select multiple Mask Blocks that occur within a single Ceiling Grid and mask them all at once, so it is probably best to place all of your instances and then apply the mask for all at one time. Once masked, you can move the Mask Block around in the same grid and it will continue to mask any part of the grid that falls behind the mask.

Next post in the series: ACA Ceiling Grids: Creating a Mask Block