The various Autodesk Revit products have the Demolish tool function that designates an element as being demolished for phasing, display, and analysis purposes, and also shows the element as dashed linework. Suspended acoustical ceilings (ACT) with gridwork are a bit of an exception as the grid does not show as dashed when the ceiling is designated as demolished. In this article, we will look at how to get the grid lines of the ceiling to display as dashed when it is demolished. In Revit 2011, the Demolish tool is found by going to the Manage tab then the Phasing panel. When the Demolish tool is used on a ceiling, only the perimeter outline is changed to a dashed appearance. The grid of the suspended ceiling still appears as solid lines. This is due to the ceiling grid not being composed of actual lines, but is the result of the grid being a fill pattern.
The 2’-0” x 2’-0” suspended ceiling grid is usually using the “Compound Ceiling 2’ x 2’ ACT System”. This ceiling type has a finish layer with the material of “Acoustic Ceiling Tile 24″ x 24″”. This material utilizes a surface pattern of “Ceiling 24×24”, which is a Model pattern fill defined in the Revit pattern file. Since that fill pattern defines the actual solid line appearance of the ceiling, that is what keeps the ceiling tile from appearing dashed.
The first step in getting a dashed ceiling grid is to create a new fill pattern which displays dashed lines in a 24”x24” grid pattern since Revit does not contain the required fill pattern by default. The following steps will add the required fill pattern to your open Revit project:
- Using Notepad, WordPad, or another ASCII text editor, create a text file named “Ceiling Grid Demolished.pat”.
- Enter the following information into the text editor EXACTLY as you see it. (Note that the editor shown below also has information needed for 24”x48” ceiling grid as well so that this one text file can be used for both fill patterns.)
- After creating the fill pattern file, go to the Manage tab, then select the Additional Settings button from the Settings panel and pick the Fill Patterns option.
- In the Fill Patterns dialog box, select the Model radio button at the bottom, then pick the New button.
- In the New Pattern dialog box, pick the Custom radio button option in the middle of the dialog box.
- Pick the Import button.
- In the Import Fill Pattern dialog box, browse to the location of the Ceiling Grid Demolished.pat file that was created above, select the file, and pick the Open button.
- In the Add Surface Pattern dialog box, select the Ceiling 24×24 Demolished pattern and then pick the OK button.
- The new Ceiling 24×24 Demolished fill pattern will now be listed in the Fill Patterns dialog box. Pick the OK buttons to exit the dialog boxes.
To get the actual demolished ceiling grid to display as dashed lines, the following process can be followed:
- Highlight the 2’x2’ ACT System ceiling.
- Go to the Properties palette and select Edit Type at the top of the palette.
- In the Type Properties dialog box (with the 2’x2’ ACT System type displayed), select the Duplicate… button.
- In the Name dialog box, type 2′ x 2′ ACT System – Demolished as the new name and pick the OK button.
- In the Type Properties dialog box (with the 2’x2’ ACT System – Demolished type displayed), select the Edit… button for the Structure parameter.
- In the Edit Assembly dialog box, go to the Acoustic Ceiling Tile 24″ x 24″ material for Finish 2  layer 4 and select the button to change the material.
- In the Materials dialog box, highlight “Acoustic Ceiling Tile 24″ x 24”, right-click and select Duplicate from the context-sensitive menu.
- In the Duplicate Revit Material dialog box, type Acoustic Ceiling Tile 24″ x 24″ – Demolished as the new name and pick the OK button.
- With the new material highlighted, go to the right side of the dialog box to the Surface Pattern option and select the newly added “Ceiling 24×24 Demolished” fill pattern.
- Pick the OK buttons three buttons to exit out of the dialog boxes.
Once the demolished ceiling grid type has been added to the project, any ceiling can be changed to the demolished ceiling type. It is important to also use the Demolish tool on the ceiling to make Revit analyze it as being demolished, as the demolished fill pattern only gives it the appearance of a demolished ceiling.
The above steps can be used for 2’x4’ ceiling grids as well simply by substituting the grid dimensions in the steps. The same fill pattern text file created above can be used as it contains both grid sizes. Please see the Help file in Revit for more explanation of creating Revit fill pattern files.
The above steps are similar in earlier releases of Revit, but the location of the tools may be different depending on the release.