Phasing and Replacement Windows

Over the years people have often complained about trying to document replacing existing windows with modern windows but maintaining the existing opening. This means swapping windows with families that are the exact same size. This is related to the wall that Revit creates to infill a wall that has a demolished window. You may have encountered this warning message?

That message appeared when I attempted to place new windows in the New Construction phase after demolishing the existing windows first. I was careful to set up views assigned to different phases and phase filters so there wouldn't be any display conflicts.

I got interested in this issue again recently because of a thread at the Autodesk User Forums for Revit Architecture. A fellow member was sharing how much trouble Revit has been giving them trying to do this kind of work. After some back and forth I narrowed it down to one window family and another member realized that family uses a void to cut the hosting wall in the family itself versus the usual opening.

This led me to write some hypotheses for testing purposes. I wrote:

Hypothesis A: Within phasing we can replace Existing Window A with New replacement Window B using the exact same sizes (same size opening dimensions) IF they both use an OPENING in the family to cut the host.

Hypothesis B: Within phasing we can replace Existing Window A with New replacement Window B using the exact same sizes (same size opening dimensions) IF they both use a VOID in the family to cut the host.

If either of the above are false then...

Hypothesis C: Within phasing we CANNOT replace Existing Window A with New replacement Window B using the exact same sizes (same size opening dimensions) IF one uses an OPENING and the other uses a VOID, in the family, to cut the host.

I did some testing using the latest release of Revit, 2024.1 and I determined the following:

Hypothesis A is TRUE

Hypothesis B is FALSE

Hypothesis C is neither

I find that I can replace a Void based window with an Opening based window but not the reverse. Also any alterations to the hosting wall in the project; such as length adjustment, or top/bottom offsets, attach/detach will place the void type window at risk of being deleted. Weirder still is that it might not delete all of them, one or more.

It seems that the short answer is: eliminate window families that use a void to cut the hosting wall IF you intend to place identical sized windows in phased projects; to demonstrate existing window replacement without altering the existing openings. Windows created this way will not work for this task. A logical next hypothesis is to anticipate similar behavior in door families.

I speculate that this warning happens because an opening cuts fully through the host while a void (or combination of voids) might cut more and/or less of the host as it travels through it. I suspect that the infill wall can't abide the shape a void might create and that in turn means a void won't be viable as a window to alter the location of the infill wall. I think it's similar to curtain walls only supporting non-rectilinear panels with the system panel families.

I'd love to hear that the developers will test this against their own experience and expectations. I know that a lot of people rely on voids to shape the opening in a host wall to match a variety of actual construction techniques for openings. To eliminate voids in families as an option for this kind of project (replacement windows (and doors?)) is not ideal. They'd probably have to revisit the entire logic of infill elements where demolished hosted elements occur. Perhaps leave it up to us to fill in holes?

Phases are Deleted - Electrical Issue - Cancel placing a wire

A client shared this issue with me a couple of weeks ago and Autodesk has acknowledged it as a bug. If you've already installed 2018.1 it has been patched, so the scary bit that follows has been dealt with.

The issue: Place the first node of a wire and then cancel (press ESC key for example) before placing the second node. Afterward, people find that their project's Phases are no longer available. In other words, the phases are not listed in the Phasing dialog box nor in the Phase parameter for elements, when examining the Properties palette. Also, the buttons that allow us to create new phases are disabled in the Phases dialog.

Bad bug! Fixed in version 2018.1.

Phases and Phase Filters Follow Up

I received a comment from a reader asking how to show all the elements in a view after having done the demolition work. The Phase Filter Show All should provide this however in this case they were attempting to show everything from a later phase. In this scenario there are three phases: Phase 1 (existing), Phase 2 (new work) and Phase 3 (the view they want to see things from).

That poses a problem because the earlier work (demolition and temporary) will not be displayed anymore because it is "gone" when you move forward in time to a view assigned to phase 3. This image is of a 3D view that is assigned to Phase 2 using Phase Filter Show All.

In Phase 3 items that were created in Phase 1 and 2 are both regarded as existing now, as long as they were not also demolished since they were created. Once they are demolished they no longer "exist" as far as that View and Phase Filters are concerned. This is what we see in Phase 3 with Phase Filter Show All.

To show all the proposed work together, Phase 1 (existing) and Phase 2 (new work) should be sufficient. In a view assign it to Phase 2 and use Show All Phase Filter. It is important to understand that elements always belong to a particular phase but their appearance (controlled by Phase Graphic Overrides) is affected by the Phase settings of the view they are seen in and that changes from view to view.

We really can only see all elements, including those that have been demolished or are temporary from a view assigned to "now" and one phase further in the past. Any further in the past than one phase and those demolished and temporary items are no longer part of our virtual world.

Which Phase Filter?

There are several phase filters that stock templates come with. Sometimes people aren't certain which ones to use or why they exist. There are three options that affect how elements are influenced by Phase Filters: By Category, Overridden and Not Displayed.

By Category - Project Object Styles and/or view's Visibility/Graphics Overrides govern.
Overridden - Revit will change the appearance of elements based on the Phase Graphics Overrides settings (see next image). Note that a Filter (View not Phase) applied to a view can still influence an element affected by a Phase Filter.
Not Displayed - Yes, this means elements are not displayed in the view.

What does it take for Revit to regard an element as being New, Existing, Demolished or Temporary? It varies according to the Phase of the view we see it in and which Phase Created and Phase Demolished parameters values are assigned to it. The following conditions define which Phase Status an element belongs to in a given view. For the following images assume this view is assigned to Phase New Construction and that we are looking at the Phasing parameters of four different walls.

New - Element's Phase Created parameter is assigned to the phase of this view and the Phase Demolished parameter is set to None.

Existing - Element's Phase Created parameter is assigned to an earlier phase than the phase of this view and the Phase Demolished parameter is set to None.

Demolished - Element's Phase Created parameter is assigned to an earlier phase than the phase of this view AND its Phase Demolished parameter is assigned to the same Phase as this view.

Temporary - Element's Phase Created parameter is the same phase as this view AND its Phase Demolished parameter is also assigned to the same phase as this view.

Any given element can belong to one of these four Phase Status in any given view according to the Phase parameter of that view AND its own Phase Created and Phased Demolished parameter settings. Phase graphics depend entirely on creating views for each appropriate phase and creating elements so they are assigned to the correct phase and then altered so their Phase Demolished parameters are assigned as required, if required.

Getting to the title of this post finally, each view has a Phase Filter parameter. What follows is my take on why I'd use each of the stock Phase Filters.

None - It's not a Phase Filter in the dialog, it's a choice in the list of Phase Filters within a view's properties. We use this when we don't want any Phase settings to affect the elements in the view. Everything is displayed according to either Object Styles or Visibility/Graphics Overrides.

Show All = This filter can't be altered or deleted. It means show us everything WITH Phase graphic alterations applied. NEW elements are governed by Object Styles (or possibly Visibility Graphics overrides) AND it overrides Existing, Demolished and Temporary elements. Use this filter to help see everything mixed together AND altered so each Phase Status is obvious. It is NOT a typical way of producing traditional documents but it CAN help explain relationships very well.

Show Completed = We're done! We don't want to see any graphical bias toward new or existing work, they should look the same. We don't want to see any demolished or temporary elements. We want to use this to show the finished design after construction is done. We could think of it as a view of "As Built" conditions if the model is kept current through construction.

Show Previous and New = We want to show new construction information in context against existing features but without Demolished or Temporary elements. This is ideal for New Construction views.

Show Previous and Demo = This is the filter to use for typical demolition documentation, existing features altered to show where demolition occurs. New work and Temporary work are not shown.

Show New Only = This is useful when we want to give a hint of future work. We can isolate and override graphics in a view to prepare a view for overlaying over another view on a sheet. When we overlay this on top of a new construction plan we'll see how they relate to each other despite the fact that Revit has no "future" phase.

Don't be fazed by phasing!

Phase and Poche Materials

As you're likely to know already Revit provides a feature to change the appearance of elements to distinguish between phases of work. When you examine the Materials dialog the "Phase-X" materials were created by the development team and they exist to support the way that feature is intended to work. The templates are configured (OoTB) to automatically "work" if you use the phase features.

When I visit the 2014 Architectural template I find three "rogue" phase materials in the dialog (image above). The four highlighted in yellow are assigned to the Phases Graphic Overrides.

I've no idea what these three other materials are assigned to. When I examine the Materials dialog and the icon for "asset use" (highlighted with the red circle in the first image in this post) the four "good" materials report that the associated asset is shared with 8 materials. The three rogue ones are not using an asset shared with any other materials. Easy enough, I deleted them. Revit will let you delete any of the phase related materials even though the Phase feature is technically relying on them to work as intended out of the box.

In general nobody will use the materials for anything else, not really suited for anything else. They "work" as intended and are preset so they do. The only real interaction anyone needs to have with any of these materials is if something about how they look isn't quite what we want. If we don't think demo elements should be red we can change the material to use something else or increase or decrease the transparency for example.

The other material highlighted in yellow is the poche material (pronounced Poe-shay). It's also a feature that was originally tied to the graphic display of the model when Coarse Detail Level is in effect. However they've made the Poche material assignment a Type Property of 3D views.

You have to assign a material to have it take effect. In the past Poche was hardwired to the effect. Now you can technically use any material in the library instead. Poche isn't required itself to work anymore. Here's an example of it being used on the section through a pavilion model.

Five Minutes of Phasing

Here's another short video in the "Five Minutes of" theme. This time I decided to delve into the basics of phasing. Due in part to the recurring assumption that I see where people feel it is necessary to add a "demo" phase. I wrote about this in the past. It's a natural assumption but not necessary for Revit's process and features to work. You can watch it at OpEd Videos or You Tube...or here.

Revit MEP and the Phase Feature

You have existing HVAC equipment. You've documented the existing system and connected everything. Once you demolish it in a later phase however it becomes disconnected in the earlier existing phase.

This comes up every now and then during discussions and a recent thread at AUGI brought it up there too. Jason Martin, with Autodesk, wrote a nice response worth echoing:

Jason wrote:

The basic problem is that things like ducts and pipes are only allowed to be connected to one other thing "per connector". If I have a duct that is connected to an elbow the connection between those two are "properties" of those two elements (i.e. the duct knows it is connected to the elbow and the elbow knows it is connected to the duct).

The secondary problem is that the "temporal" concept in Revit (phasing) is primarily a "display only" concept (there are some special cases where other things are done, but primarily it is limited to display). I'm not arguing that adding temporal intelligence to these elements isn't a good thing, as there are a number of other cases that it would solve (i.e. like the ability to move something that exists in "this" phase to a different location in a "future" phase phase), but it isn't there today.

From a practical standpoint this means the mantra of assign stuff to systems can't be met completely with existing demolished stuff. Something I'm sure the designers at Autodesk are wrestling with internally.

With regard to the AUGI thread and getting the appearance of the documents they wanted, Jason went on to suggest that they use Filters based on a different parameter than System Type since that parameter is lost when the elements are demolished.

Existing Rooms and Their Tags

Demo plans need room tags so a contractor knows what room to demo stuff in. Room tags can't tag a room in a demo plan because the current phase is set to new construction.

How can you get room tags to identify the existing rooms? Overlay views on a sheet.

Create a new view assigned to the Existing Phase.
Using Visibility/Graphics turn off all Model categories except Rooms.
Now your view only shows rooms and room tags.

On the sheet that displays the demolition work, overlay this special room/room tag only view above the demolition view. A little bit of extra work but you get automatic display of the correct room information without resorting to "dumb" text and introducing possible errors.

As an aside, I believe that rooms should behave more like other model elements and have a "Phase Created" and "Phase Demolished" parameter. This way an unaffected room can persist across phases. Rooms whose boundaries are demolished should also be demolished and require the creation of a new room. In this way a demolished room would still be visible and New rooms would not according to the view's Phase Filter setting. I'm sure there may be some programmatic conundrums that this might introduce but overall this is the sort of manner in which Rooms should behave...in my opinion.