Revit MEP - Silly Revit - We Don't use those Pipe or Duct Sizes

If you don't take the time to fine tune your project templates then you'll find Revit will offer you all kinds of pipe and duct sizes. These are available in the drop down lists during placement and then later if you run Duct/Pipe Sizing.

If you don't take the time to fine tune your template you'll find Revit gives you a duct size of 11" after completing its Duct Sizing, regardless of the fact you only choose from even sizes. It's easy to blame silly Revit...but it's our fault. The Duct and Pipe Sizes are controlled via Mechanical Settings, the duct sizes for Rectangular are shown below.

We need to either delete sizes we never want or just un-check them in either column or both, Set it and forget it.

Oh, the same is true of conduit and cable tray.

Revit 2016 - Loss Method and ASHRAE Tables

Fittings and loss errors have been annoying in Revit MEP for quite some time. If we were striving for a warning free model then we'd be confounded at every turn by fittings and their loss for loss. In Revit 2015 R2 and 2016 we've got the option to assign fitting's Loss Method parameter to Coefficient from ASHRAE Table.

The ASHRAE Table Settings dialog displays graphical information that is associated with duct fittings table. We can choose from among the fitting descriptions in the table or accept the default one that is already selected.

If you select a fitting randomly and check this out you may find the dialog set to None. It only starts to work when components are well connected. That means, if you see warnings associated with fittings, its likely those fittings are not part of a well connected network yet.

Revit MEP Family Wisdom - Family Origin

Another tip snipped from the Revit Family Editor Tutorial for Revit 2008 as mentioned in the previous post. You can download the PDF copy HERE.

Fittings (duct, pipe, conduit and cable tray fittings) expect the instance origin of the family to be the (projected) intersection of the connectors. In most cases for fittings, there is a point on the fitting where all of the connectors (if extended into the fitting) will collide. Fittings expect this collision to be placed at the original intersection of the Center (Front / Back), Center (Left / Right), and Reference Level work planes. For this reason, it is good practice to pin these reference planes before beginning to build the family.

Revit MEP Family Wisdom - Shape Handles

Another tip snipped from the Revit Family Editor Tutorial for Revit 2008 as mentioned in the previous post. You can download the PDF copy HERE.

Shape handles are not used for Revit MEP system families but they display by default when you create a new family. If shape handles are not hidden and they are inadvertently dragged during your modeling session, the geometry or placement of the family will be adversely affected. This can create unexpected results, especially for duct fittings. This is because, unlike pipe fittings, duct fittings use formulae that reside in the family rather than in an external lookup table file to determine size.

It is highly recommended that you hide all shape handles for Revit MEP families before using them in a project. To hide the shape handles in a system family, you need to open the family in the Family Editor and specify the Is Reference instance parameter as Not a Reference for all reference lines and all reference planes that are used for that family.

Before on the left / After on the right

Revit MEP Family Wisdom - Connector Arrows

Another tip snipped from the Revit Family Editor Tutorial for Revit 2008 as mentioned in the previous post. You can download the PDF copy HERE.

Connector arrows indicate the direction of a duct or pipe (extrusion) when it is being created to complete a connection. It does not indicate flow direction. In most instances, a connector arrow points outward away from the object to which the connector is associated. Otherwise, the duct or pipe when created will pass through the object geometry instead of away from it. You can modify the connector arrow direction by selecting the connector and clicking the flip arrows.

Revit MEP Family Wisdom - Connector Orientation

This is snipped from the Revit Family Editor Tutorial for Revit 2008 as mentioned in yesterday's post. You can download the PDF copy HERE.

Connector rotation is a critical part of connector placement. The connector orientation determines the correct orientation of the objects that are automatically inserted on the part. Although this is not as important for round connectors, it is extremely important for rectangular connectors such as those on rectangular duct fittings. Remember that for rectangular connectors, the rectangular connector must be oriented so that the width is assigned to the face that is on the X and Y axes. The height is not on these axes. If rectangular connectors are not rotated properly, the rectangular duct fitting will be inserted improperly, creating an unexpected result. You may find it easier to rotate connectors in a 3D view, where the part geometry is clearly visible.

Revit MEP Family Wisdom - Connector Placement

This is snipped from the Family Editor (Imperial) Tutorial provided with the Revit MEP 2008 release. I don't believe there is a more recent version of it unless they have incorporated some or all of it into the current help documentation online. Some of it certainly was part of the previous WikiHelp site but I haven't checked to see if everything is now part of the new online help yet.

You can download PDF copy of the tutorial HERE.

When you place fitting connectors, the primary connector must be placed on the face that is on the X-axis. You can verify this by viewing the face in a floor plan view. Unexpected behavior can result if the primary connector is not properly placed relative to the other connectors, and that if all connectors are not properly rotated and linked.

The primary connector is the one that has the crosshair or "X" in the connector graphics. You can also Reassign Primary on the ribbon when the connector is selected.

This pearl of wisdom also appears at the beginning of the Creating an Elbow Family topic:

Fittings are among the most complex families to create. It is recommended that you methodically follow the steps and periodically check your work against the exercise. It may take a longer to complete this exercise as compared to other exercises in this tutorial. Even if you have created parametric families before, creating system families typically takes more time to complete.

Revit MEP Annotation Scale

In the settings dialog for duct, pipe, conduit and cable tray Revit provides a parameter called Use Annot. Scale for Single Line Fittings. There is also a second related parameter called "XXX Fitting Annotation Size" where "XXX" is the element involved. As the parameter names suggest they are related to single line views, where the detail level is either assigned to Coarse or Medium for their category (duct/pipe/conduit/cable tray).

When the first parameter (previous image) is checked Revit will check (turn on) the parameter that each fitting or accessory has, called Use Annotation Scale, each time they are placed in your project.

The purpose of these related settings is to provide a consistent symbol size regardless of view scale (in single line views). This way the symbols don't suddenly become much larger or smaller in different scale views than the symbols we show on our legends. When you see this occur you'll need to double check the settings and the individual parameter values for each affected family.

If the option is off in the Settings dialog then every fitting or accessory you place has its own Use Annotation Scale setting unchecked (off). It's a global on/off switch to enable the feature. You can still interact with each fitting or accessory's own parameter to enable the annotation scaling feature or vice versa. When you change the view's scale you'll find that the annotation symbol graphics will not remain the same printed size.

The following image shows one ball valve accessory that has had its Use Annotation Scale turned off. It's larger than the other fittings and accessories in the view, they adjust their symbol size so they are the same size when the views are printed on a sheet. The lower plan view is using 1/4"=1'-0" scale and the upper one is assigned to 1/8"=1'-0" scale instead.

This image is both views placed on a sheet for comparison.

Each of these MEP element has its own settings; Duct, Pipe, Conduit and Cable Tray. I think the most appropriate setting for each is checked (on). The second parameter XXX Fitting Annotation Size is usually 1/8" ( or 3.0 mm) (stock setting in templates) and that's probably a good starting point. You may find it necessary to adjust it slightly by increasing or decreasing the size to get the ideal symbol graphics.

The other thing to keep in mind is that the single line graphics in these families are defined by Model Lines that are set to be visible in Coarse and Medium Detail Level but to not be visible in Fine Detail Level. This makes it possible to generate the single line diagrams in 3D views too, otherwise there would be nothing to see. It also makes it a bit trickier to get the same graphic size when comparing one fitting or accessory with another.

This is quite different from electrical families by comparison because those primarily use nested annotation symbol families for their symbolic graphics. Those already conform to Revit's annotation behavior of maintaining their printed size. It also explains why, for electrical components, 3D views (and elevations/sections) do not show the plan graphic symbols we are accustomed to seeing.

Fittings Do Not Look Right

A troublesome thread popped up at RevitForum.org the other day and DMapes came to the rescue. I haven't encountered this peculiarity before, and now that I know about it it's a bit surprising that I haven't. I guess I've just been lucky.

When you use the Underlay setting in Revit MEP you run the risk of altering the way your pipe fittings (duct fittings too in views using Detail Level: Coarse) scale and/or look. Here's a good and bad side by side.

The pipes on the left are good but those in the view on the right are smaller and halftone, as a result of using the Underlay setting.

Set to None the fittings look correct, but using the same level the fittings are associated with as the underlay equals sadness. It doesn't seem to mind if you use other levels as the underlay though. Careful with your underlay!

Dept. of Subtle - Flipping a Fitting Replaces Other Fitting

This is a follow up to last Friday's post about sloping pipe. After using the Slope tool you might have noticed that a couple fittings were reversed. When I used the "flip arrow" to fix them I realized that another fitting nearby was affected too. A fitting getting flipped is effectively changing the slope of the pipe slightly because the origin of the fitting is altered slightly. The larger the fitting and the more eccentric the shape the more it can affect the piping. I created a second VIDEO to explain it further.

New Revit MEP Content via Subscription

Echo...new content at available for Revit MEP subscription members. Stephen Roth, the new product manager for Revit MEP writes, on the Inside the System blog:

I am pleased to announce two new content extensions for Revit MEP 2009 that are available on Autodesk Subscription Center:

The "US Content Extension for Revit MEP 2009" contains imperial and metric duct and pipe fitting families that adhere to SMACNA and ASME standards, respectively.

The "UK Content Extension for Revit MEP 2009" contains duct fitting families that adhere to the DW/144 UK industry standards.

Please log on to Subscription Center and click the link labeled either "US Content Extension for Revit MEP 2009" or "UK Content Extension for Revit MEP 2009" to go to the web landing page that allows you to download the content. A ReadMe file exists that explains how and where to install the files.

This content was developed based upon feedback from users like you, so we do appreciate your feedback.

Revit MEP - Lookup Tables

[Edited December 9, 2011]
If you wish to repath the Lookup Tables for your office to a new location you'll need to consider that Revit 2012 has changed things a bit. The path may also be stored in a second Revit.ini file associated with your user profile (to better support user specific options).

The default installation should be here:

C:\ProgramData\Autodesk\RME 2012\Lookup Tables\Revit.ini

The user specific one is probably in a folder like this one:

%USERPROFILE%\AppData\Roaming\Autodesk\Revit\Autodesk Revit Architecture 2012\Revit.ini

If you find Revit is unresponsive to your new location, check the user folder location. You can read more about it in a Revit Clinic post from August 2011.

Original Post follows:

Pipe Fittings use a special folder to determine the correct fitting sizes when you create or change piping. The path may vary a bit depending on the operating system you are using. The folder, called Lookup Tables, is stored along with the content library, wherever that may be on your computer. This location is found in the Revit.ini file too.

If you move the folder elsewhere and change the location in the .ini file Revit doesn't acknowledge it. It still looks in the default location and now your fittings don't work. Seems to be hardwired...seems buggish to me.

Perhaps they didn't intend to give the impression that it could or should be moved to a central location? They don't even have a topic for lookup tables in the help documentation. Try a search for "Lookup" or "Lookup Tables"...no results.

The impression that it can be moved is given by the inclusion of the location in the Revit.ini file. Not the sort of thing your average "bear" will notice but those implementation minded "bears" will..guaranteed! In fact that's why I know about this...a fellow "bear" asked me about it! Now you do too!

Revit MEP - Fittings Get Unresponsive

If your plumbing fittings fail to adjust their size properly when you place them or when you trim or otherwise connect pipe it is time to get suspicious about the path for your Lookup Tables. Revit installs fitting lookup files that match the name of each fitting supplied in a folder called "Lookup Tables" in your content folder location. Each file is a comma delimited text file which means the information is separated by commas and the file extension is .csv.

For stand alone installations the default location is:

C:\Documents and Settings\All Users\Application Data\Autodesk\RME 2008\LookupTables

Network installations could be anywhere from the "D-Z drive" unfortunately.

Regardless this location is stored in your Revit.ini file located here (default installation location):

C:\Program Files\Revit MEP 2008\Program

If the actual location and the one stored in Revit.ini are different then your fittings will not resize graphically until they match. You'll need to close and restart Revit to get it to re-read the .ini file.

Last, there is no place within the Revit user interface to check or alter this location which I think ought to be changed and included within the Mechanical Settings dialog in the same way the Pipe Sizes.xml location is presented.