Group Editing and Ceiling Hosted Elements

Aaron Maller let me know about an unpleasant bug he's encountered in both Revit 2015 and 2016. If you're thinking, "Boy I'm glad I didn't listen to Steve's rant yesterday." Point taken... It's the exception though, not the rule.

Simple steps to reproduce the issue:

• Create a new project
• Create a ceiling
• Place at least two light fixtures (faced based or ceiling based)
• Create a Group (of the ceiling and both fixtures)
• Copy the Group to create several instances
• Edit the Group
• Swap or move one fixture
• Finish the Group

Where did the other fixture go? It (they) is (are) Excluded. If you select the Group you'll see Restore All Excluded appear on the ribbon. If you use that tool you'll find the fixture is no longer hosted by the ceiling though. It will report in it Host parameter.

If you'd like to avoid this issue then:

• Edit the Group
• Make the changes you need
• Select all the fixtures
• Nudge Up and Nudge Down to put them back in the same spot
• Finish the Group

The copies should be intact, no excluded elements.

I've also found that I can use Save Group, edit the Group in its own file and then use Reload to refresh the Group in the project. This doesn't seem to suffer from the same affliction. Take it slow if your project is using a lot of groups with ceilings. The issue doesn't seem to affect elements hosted to walls, not in the testing I've done so far at least.

Here's a video example of what happens and using Nudge to avoid it.

Need a Ceiling Tool

Revit Workflows and Auto Floors Builder are two 3rd party applications that tackle the task of creating floors more efficiently. Revit Workflows is focused on finish floors and Auto Floors Builder has a more structural focus. While I think Autodesk ought to tackle this sort of refinement directly it is great that there are some options.

Where are equivalent tools for creating ceilings? Is the API holding development back or are they just still on the drawing board? My inquiring mind is curious...

Tagging Elements and their Area

Revit allows us to tag rooms and spaces to display their area. If I'm tempted to do the same for Walls, Floors, Ceilings or Roofs the list of available system parameters (built into Revit) does not offer Area. Revit MEP users can tag a Duct's area.

It seems to me a bit arbitrary to disallow the tagging of data that is part of the element. We can see it in the element properties and include it in schedules. While a schedule is an ideal way to summarize data a floor plan is useful to provide context AND display a variety of information, like area.

It would be excellent to see more parameters unshackled.

Speaking of Soffits - Ceiling Wish

In light of yesterday's post I wish we could unlock the layers of ceilings like we can for walls. In this image I've unlocked the Gypsum Wall Board layer so I can pull it down to the ceiling surface.

If I want to reverse the relationship and install the ceiling board so that it covers the bottom edge of each soffit I can only use the Cut Profile tool in a section view, which is view specific, not a modelling alteration.

Or perhaps use separate ceiling types for the finish layer of the ceiling apart from the framing of the ceiling. If we could just unlock the layer like walls can it would make it easy to "pull" the finish layer over instead.

Another wish for ceilings? Create by Face would be cool!

Soffit Conditions

I received an email the other day asking for my opinion about modelling soffit conditions. In this particular case they used a thick wall to wrap a steel beam but then worried about the results when using clash detection later between the wall and beam. Since they overlap one another it would be a clash. Determining what constitutes a valid clash when modelling and who is modelling and then doing the clash detection is a deserving topic on its own.

My response is that I prefer to "model it like we build it" as much as is reasonable or possible. In this case I'd take this approach. I'd model the ceilings, one type on either side of the beam and another for under the beam (assuming "hat" channels for structure). I'd use a separate wall type (also assuming "hat" channels for structure) for the soffit "wall" so I could adjust where the gypsum wall board started and stopped.

Here's a section view.

And a 3D view.

In early design I could probably just get away with creating the ceilings and add the walls later when sections were needed.

Moving Ceiling Grid Pattern

Scott wrote about an issue at Revitforum.org the other day. He's been using Revit about as long as a person could use it so if it trips him up I'm betting it trips up others too!

Jesse came to the rescue with advice that perked up my Dept. of Subtle ears. He wrote:

"When you tab through to the ceiling grid while in the move command, look near the top (meaning Options Bar) at the "disjoin" check box. Revit will automatically remember if you had this box checked the last time you used the move command. It's going to be greyed out when moving a hatch pattern, and when it's checked you can't move the pattern.

To fix it, select something else, do the move command, uncheck the check box and press escape to cancel. The next time you go to move the ceiling grid the box should be unchecked!"

It's easy when you know how? :) Thanks to Jesse!

Dept. of Echo - Don't use the Basic Ceiling

Originally posted here August 2009 and still true with Revit 2013

When an architect uses the Basic Ceiling-Generic type they are creating a situation for the Revit MEP user they may not be aware of. Face based content does not orient themselves to the correct side or face of this ceiling. For air terminals and others this means they are usually upside-down. I created a short video to demonstrate what I'm writing about.

You can listen and watch below:

Here's an image to convey the issue without watching the video. The left side is a Basic Ceiling and the air terminals are upside down. The right side is the Compound Ceiling and the air terminals are okay.

Ceiling Grid in Navisworks

Revit doesn't export the grid pattern of ceilings when you export to Navisworks. The grid pattern is really just a "hatch" pattern, fill pattern in Revit lingo. No joy if you want to see the grid in your export to .NWC. I responded to a post at RevitForum.org last week with this approach to get a fairly realistic result in Navisworks.

I'm to inclined to distort the use of Sloped Glazing (roof tool).

The steps are as follows:

• Create a mullion type that is the dimensions or even the actual profile for the tee.
• Assign it to the Sloped Glazing roof type.
• If you want the wall "L" create a different mullion type for that, assign it to the boundaries.
• Assign the Empty Panel curtain panel type.
• Pick wall to define the boundaries of the "ceiling grid".
• Use a regular ceiling without a pattern set to the drop-in tile thickness and let them occupy the same space.

Get a little further carried away and use panels for the ceiling tiles. Put empty panels where non-hosted light fixtures should go in the "holes" for the lights. I used this approach a few years ago to render a room so I could experiment with getting better depth at the tile and tee edges etc.

Looks like the attached images:

Navis 3D view

Type Properties Dialog

Revit 3D View

Revit MEP–Plenum Spaces and Ceilings

I’ve noticed that Spaces and Ceilings can affect Revit MEP’s ability to display the Space element. I’ve seen it happen and then later correct itself magically. Not likely that it is magical, more like something was adjusted that changes the conditions in the first place. I admit I don’t know yet what that “magic” is.

The conditions for this to occur begin with the addition of a new Level to manage plenum areas in the building. When this new level is added and a view is created it’s a good idea to adjust the view range so it matches the available distance between boundaries. Initially it would be easy to expect this to be the reason that a Space doesn’t show up. When we add a space this error message will usually pop up.


Changing the elevation of the ceiling or the level or some combination will result in Revit being able to show them again. I created a VIDEO that DESCRIBES how the ceiling elevation and the space properties conflict with one another.

[Addendum: January 25,2011]
The issue described above has to do with the Room Computation Height of the Plenum Level, which is a Level Type parameter. The typical Level Types in Revit Templates set the Room Computation Height to be “Automatic”. This really means that the default is 4’ from the Level unless Revit encounters objects in/at the 4’ level. If Revit find issues, it adjusts the Room Computation Height to the Level plane instead.

In this case, the Level type (used for all the levels) uses the Automatic setting, so Revit defaults (when dealing with the Plenum Level) to the Ceiling Level to find the Space extents when it encounters the slab at the 4' elevation. When the bottom edge of the Ceiling Element gets nudged to align with the Ceiling Level, Revit can no longer find a closed circuit.

The solution here, and one that can be generally used, is to create a new Level Type to use for Plenum Levels, and explicitly set the Room Calculation Height to something like 0’ 6”, so the Space will always be cut inside of the Plenum Space.

Thanks to Kyle Bernhardt for the explanation!

Dept. of Subtle - Ceiling Types and RME

I mentioned this item in a tweet the other day after I finished and scheduled it for posting.

When an architect uses the Basic Ceiling > Generic type they are creating a situation for the Revit MEP user they may not be aware of. Face based content does not orient themselves to the correct side or face of this ceiling. For air terminals and others this means they are usually upside-down. I created a short video to demonstrate what I'm writing about.

You can listen and watch below:

Here's an image to convey the issue without watching the video. The left side is a Basic Ceiling and the air terminals are upside down. The right side is the Compound Ceiling and the air terminals are okay.

Dept. of Why? Auto Ceiling and Multiple Ceilings

I should start an informal poll on how many users have created multiple ceilings in a room because the Auto Ceiling function does not discriminate against multiple ceilings in the same location. When you try to put other elements in the same location as another Revit howl's in pain but not the ceiling tool. It's says, "Go for it dude...make as many as you like! It'll just confuse you later and it'll be like..kewl...I'm so like sitting back here and chuckling at you!"

I think something like twenty was the worst I've encountered. It goes something like this..."Steve, why can't I delete this ceiling?" I use a crossing selection window and filter out the other elements and find 20 ceiling elements. I tell them they placed 20 ceilings and they WERE deleting them just not ALL of them. I then wonder how many he deleted and how many there were originally?!?

He says,"How did I do that...oh wait? I placed the ceiling but I didn't see it at first so I tried again, and again and again and again..." This happens the most with the GWB ceiling type that doesn't have a material assigned to the GWB which means you can't "see" it. You aren't convinced there is a ceiling so you keep clicking! Remember a definition of insanity is doing the same thing repeatedly expecting different results.

I'd like the ceiling tool get a bit smarter, a bit more discriminating. Which reminds me the ceiling tool ought to be able to detect columns just like rooms!!