A lot of people ask me if I’ll give them my Iplex floor waste gully family. The answer is always no, not because I don’t want to share, but because I would rather people learn and understand for themselves rather than taking the easy way of “grabbing something from the internet”
I recorded a video on how to create the FWG a long time ago, but after a bit of back and forth discussion on Youtube, I have decided to pull that old video out and record some voice annotation so you can follow along.
I do apologise about the audio quality, I only had my junky work headset to record with.
Yes, this is how I spend my nights in hotels when travelling for work.
It’s clear how lookup tables are beneficial to the pipe and conduit modelling process, so how can we use them in other Revit family categories?
Originally lookup tables were only available to pipe and conduit fittings, but we can use them in any family category. We can build fully flexible families that a controlled with lookup tables, we just need to use a bit of common sense when deciding if a lookup table is best suited or not.
Valves would be suited quite well to utilising lookup tables, whereas a VAV box would be more suited to using formulas and other parameters.
Building Your Own Lookup Table
You can use dimensions, angles and integers to both look up and be looked up, the trick to working with integers is that your column header format should follow
Using integers can be valuable within lookup tables to control the dimensions of specified manufacturer equipment. To achieve this, we need to take the manufacturer sizes and populate them into a lookup table. Working this way locks down the sizes so that the end user is unable to manipulate them. In this example, we’re going to work with a basic rainwater tank.
Rainwater tanks are a perfect use of lookup tables, you could have a family file that contains data for one manufacturer, then the lookup table drives the dimensions based on the volume. We use the volume value because this will drive all other dimensions of the tank.
We’re going to use an integer parameter for our tank volume, as volume parameters can not be used in lookup tables.
This is our basic lookup table to get started with. We’re going to look up the volume as an integer which will in turn drive the tank diameter, height and inlet height dimensions.
You can see that based on our basic lookup table and our lookup formulas, the correct data is being input into the family.
Once the lookup table is populated with the tank dimensions across the product catalogue, all a user needs to do is change the tank volume to a value that corresponds with one in the lookup table and all the dimensions will automatically update.
A trick that can be used with lookup tables is that we can drive a single text parameter with a lookup table, the same old restrictions apply though, if you’re looking up an instance parameter, you must be driving an instance parameter.
The secret behind bringing text in from the lookup table is to leave the lookup column in the formula blank. In our rainwater tank example, that would read as follows
Getting More Advanced – Allowing Custom User Input
The example water tank is great when you want to completely lock down a family, but what if you want the option to allow input form the user? We can allow for this by adding a few additional parameters to the family.
To achieve this, we’ll add a yes/no parameter to the family which can be checked when the user wants to specify a custom size. When checked, this parameter will override the lookup table.
We then need to add parameters within the family for every parameter that is controlled by the lookup table.
The new parameters that have been created in the family are CustomDiameter, CustomHeight, CustomInletHeight and CustomTankType.
We now need to change the formulas for each parameter being controlled by the lookup table so that the lookup formula is nested within an if statement.
This also allows our trick with the text lookup to make it very clear that custom dimensions are being used, as we’re changing the TankType parameter to read “CUSTOM DIMENSIONS”
Modifying Existing Pipe Fitting Lookup Tables
Now that we know everything there is to know about lookup tables, modifying existing lookup tables should be quite easy. For this example, we’re going to use a PVC pipework bend.
You can download a copy of the files I’m working with here
Open the family
Open the family type dialogue
Click on the Manage Lookup Tables button
Export the existing lookup table
Rename the lookup table to Bend_PVC_DWV_Iplex.csv
Back in the family types dialogue, import the new Bend_PVC_DWV_Iplex.csv and chance the Lookup Table Name parameter to Bend_PVC_DWV_Iplex
Apply the changes and close the family types dialogue before continuing.
We also need to refer to the Drain, Waste & Vent Pipe table on page 23 for information about pipe diameters and wall thicknesses
Open the .csv file in Excel. The out of the box (OOTB) lookup table is in inches, it is up to you if you convert the current dimensions to millimetres or not, but we will need to change the column headers from inches to millimetres (USA spelling)
Compare the dimensions of the Iplex product catalogue with that of the Revit family.
L1 – L2 (from fitting table)
Centre to Socket Bottom (CtSB)
L2 (from fitting table)
Socket Depth (SDpt)
a (from fitting table)
L1 (from pipe size table)
Fitting Outside Diameter (FOD)
L2 (from pipe size table)
Wall Thickness (WThk)
Something to take note of is that the L1 dimension from the pipe fitting takes into account the total length of the fitting from the centre of the fitting to the end of the fitting including the socket.
Within Revit the Centre to Socket Bottom does not include the socket, so the figure that we need to take for CtSB is actually L1 – L2
In this example, I’m going to start with the 40 dia fitting size, however if you have a need for the 32dia pipe fittings you can start there.
There are 3 different 40 dia elbows in the Iplex catalogue. 40×15°, 40×45° and 40×90° each with differing dimensions. To allow for each specific fitting, we’re going to add a row for each fitting from the catalogue.
Fill out the corresponding data to the lookup table from the Iplex catalogue, once done, save the csv file and load it back into the family and test the flexing of your new 40 dia fitting.
If you’re happy with how the family flexes for your 40 dia fitting, continue adding the remaining sizes to the lookup table.
Once you’re finished you’ll have a complete, dimensionally accurate Iplex PVC pipe fitting.
Life isn’t just about Dynamo, so here is something a little different to mix things up.
Earlier this year I spoke at BiLT ANZ 2017, I had the opportunity to present two separate talks of which one was lookup tables. It’s a bit of a dry topic, so stick with me.
Lookup tables for pipe and conduit fittings provide an invaluable enhancement to the MEP workflow that we take for granted. On every project we work on, lookup tables save us countless hours in the modelling process. Without them, modelling a pipe system would require each individual pipe fitting to be sized as you go. It may be only a few seconds lost per fitting, but multiply that by hundreds or even thousands of times across a project. Then consider the revisions across the piping network. Those few seconds wasted quickly adds up.
At their core, lookup tables are simply comma separated value files (.csv) that are used in conjunction with Revit family files. Prior to Revit 2014, these files were stored on your hard drive or in a common network location and that location was referenced by the revit.ini file.
You might have had experience with tiny pipework fittings that wouldn’t size correctly in Revit if the lookup table location was not correctly configured. Nowadays, lookup tables are stored within the family themselves, provided your family content has been properly updated to 2014 or newer the new system with embedded lookup tables should eliminate those tiny fittings altogether.
Most commonly lookup tables are used for defining pipe and conduit fittings based on the nominal diameter of the fitting. Revit is then able to automatically size and resize fittings based on the size for the pipe the fitting is connected to by using the data contained within the lookup table.
The Lookup Table Format
Lookup tables can be created and edited in either a simple text editor such as Notepad or Notepad++ or in Microsoft Excel and it’s alternatives.
The first column is a reference column, the values in this column could be ‘Tom’ or ‘Jerry’ but it’s obviously more useful to give enter data that is relevant to the family being created.
Usually when dealing with pipe and conduit fittings this is the nominal diameter, when dealing with pipework branches, I like to format my references as Upstream x Downstream x Branch so for example, 100x100x65. You could however include product names, say if it was a 5000 litres grease arrestor, the reference could be GreasePit5000
The second column defines the lookup value which is typically the nominal diameter of the fitting. This is the column that Revit will look up to determine the remaining parameters for the element.
The formatting of the headers within the csv file is
which you can see in the example above. The formatting of the headers is critical for the lookup tables to work.
In column B of the example, we have ND##length##millimeters (note US spelling of millimetres) which in this to the nominal diameter, it’s a length parameter and the units are in millimetres.
If further lookup values are required, say for example in the instance of a pipework branch, more lookup columns can be added as needed, shifting the remaining columns to the right.
As you can see in the above example, we have three nominal diameter columns to determine the size of our fitting.
The remaining columns after our lookup columns contains the data that drives the modelled dimensions of the Revit family and you can have as many lookup columns as you need to generate your family.
How Lookup Tables Are Used in Revit Families
Lookup tables are stored within the family file itself through the Manage Lookup Tables dialogue. The lookup table is then referenced using a text based parameter and lookup formulas are used to retrieve these values from the lookup table.
Importing and Referencing the Lookup Table
To import the lookup table, you first must open the family file itself. In the family types dialogue box, click on the Manage Lookup Tables button.
Once in the Manage Lookup Tables dialogue, you have the option to either import or export the lookup tables contained within the family.
If you’re starting with a family that already has an associated lookup table, it’s always a good idea to start by exporting the original lookup table so you can use that as a base and then modify.
Once you have a completed lookup table, you can import it in the Manage Lookup Tables dialogue. You can have multiple lookup tables within your family files and chose whichever is required.
Once the lookup table has been imported, you need to add a text parameter to the family that references the lookup table name. Historically this parameter has been named Lookup Table Name although you can name this parameter anything that you like, it’s best to remain consistent with the out of the box parameter naming.
When filling out the parameter data, it needs to match the name of the .csv file that you are going to use, minus the .csv extension.
Lookup Table Formulas
The formula used to reference the lookup tables is
size_lookup (Lookup Table Name, “Lookup Column”, Default If Not Found, Lookup Value)
The format of the formula is similar to that of an if statement.
The first portion of the formula is telling Revit to find a value in the lookup table “Lookup Table Name” for a column named “Lookup Column” and then pull the value from the row that corresponds with the value from the “Lookup value”. If there is no match, Revit will provide the value from “Default If Not Found Value”.
In the example above, the formula is finding the value for the fitting outside diameter.
Stepping through the formula, Revit will lookup the table that has been defined in the parameter Lookup Table Name for a value in in the column named “FOD” that corresponds with the lookup value of the Nominal Diameter parameter (50mm). If no match is found for the nominal diameter in the lookup value column, a value equal to Nominal Diameter 1 + 9.1mm will be returned.
Note that the nominal diameter is currently set at 50mm. If we refer to our csv file we’ll see that our lookup value is ND1 which corresponds with Nominal Diameter 1 in our family.
When ND1 is 50mm we can see that the value of FOD is 56mm, this has set our family to have a fitting outside diameter of 56mm.
What About Multiple Lookup Values?
You may have noticed that the example family used is a DWV pipe branch fitting, so we need to deal with multiple lookup values. The fitting may be a reducing branch or it may have different variations in branch angles.
To achieve this, we simply need to add more lookup values to the end of the formula.
In this example we’re looking up the socket bottom to socket bottom run, we are again referencing the same lookup table however this time we’re looking for a match for Nominal Diameter 1, Nominal Diameter 2,Nominal Diameter 3 and Angle in a single row within the lookup table.
If a match is found, Revit will return the value from the column that corresponds with SBtSBR. If no match is found, Revit will return a value equal to that of Nominal Diameter 3 + 27.7mm.
This particular fitting we are working with is a 50x50x50 x 45° DWV branch
Referring to our csv file, we can see that when we look up the values 50, 50, 50 and 45 the corresponding value in the SBtSBR column is 81mm which is the value that has been set in our family.
Remember that the lookup columns need to be in order in columns from left to right to be able to lookup multiple values.
So that’s it for understanding how lookup tables work, stay tuned for Part 2 where we look at applying the use of lookup tables to improve our workflow.
One of the gripes that a lot of hydraulic engineers and modellers have with Revit is the representation of pipework bends in 2D views. It’s something that I fixed up pretty early on, but I’ve come to realise when I come across drawings that look similar to the screenshot below that some may still not know how to fix this.
I’d a quick fix per fitting, the problem will be if you have a lot of fittings to modify, it becomes a long repetitive process.
The first thing that you want to do is to edit the family, and switch to the Ref. Level view, you will be greeted by something that looks like this:
In this instance I am modifying the out of the box Revit family Elbow – Soldered – CU.rfa. If you’re little overwhelmed by what you see on the screen, don’t worry; we’re not touching any of the dimensions or 3D elements. If you need to, you can adjust the scale of the view to change the size of the dimensions, or you can completely turn off the dimensions in Visibility/Graphics (VV / VG shorcuts).
What we are wanting to change is the 2D representation of the fitting, which are model likes of the pipe fitting subcategory. In the screenshot below, I’ve highlighted them in red with the dimensions turn off for clarity.
When modifying the pipe fittings, I like to keep the original linework in the family as a just in case. I usually change the linework to the <Invisible Lines> subcategory or turn the visibility off, you can however remove them if you wish.
To achieve the clean 2D representation that you’re used to, we’re going to create some new linework along with a reference line to control the angle.
First up, find the intersection of the Front/Back and Left/Right reference planes, from the intersection, draw a model line using the Pipe Fitting subcategory on a 45 degree angle (1) and then create an angular dimension between the Front/Back reference plane and your newly created reference line (2)
When you start drawing your line from the intersection of the two reference planes, Revit will automatically lock your line to the intersection point, this is also the point the the fitting is scaled around.
Next, apply the angle parameter to your dimension, the line will snap around to the same direction as the fitting.
You now need to align and lock the endpoint of your line to the reference plane for the outside edge of the fitting.
Now draw the other half of your fitting symbol. You don’t need to apply an angle in this case, just draw the line from the intersection of the Front/Back and Left/Right reference planes to the outer edge of the fitting. Don’t forget to align and lock the line to the outer reference plane.
Once you’re done, flex your fitting within the family editor, changing the diameter and angle. Make sure everything works as expected.
Now load your fitting back into your model or template and check out the difference
For the tee fitting, there is no need to recreate the symbology from scratch, all you really need to do is to remove the ticks by either making them invisible, or changing them to the <Invisible Lines> subcategory.