The Building Coder

The Dynamo Revit Unit Test Framework

I have repeatedly underlined the importance of unit testing, and recently presented the RvtUnit project enabling the use of the NUnit unit testing tool for Revit add-ins. The Dynamo team now presents another one; in case you have not already heard of and explored it, Dynamo is an exciting visual programming tool on top of Revit. The best explanation of Dynamo is provided in the Dynamo GitHub repository. Much of the discussion and suggestions for new features etc., is happening... Read more →

Load Your Own External Command on the Fly

How to reload an external Revit command without having to restart the Revit session has been a subject of discussion many times in the past, e.g. in reloading an add-in for debug without restart, which lists four possibilities: Set up Visual Studio to efficiently load the desired project and the debugee, use the standard cycle hitting F5 to start debugging, and stop debugging when you need to make code changes. Use the RevitRubyShell or RevitPythonShell to work interactively with the... Read more →

Filter for Family Instances in a Room

I wish you a Good Friday. Continuing the research and development for my cloud-based round-trip 2D Revit model editing project, I need to determine the boundary loop polygons to represent the furniture and equipment family instances for manipulation on the mobile device. Before I can start extracting their geometry, I need to access the objects themselves, i.e. determine which family instances are contained in the selected room. As always, we use a filtered element collector to access the Revit database... Read more →

Determining Purgeable Elements

A question that crops up from time to time and is rather hard to answer exactly and exhaustively is on purgeable elements: Question: What is the best way to get all of the elements that can be purged? I can use WhereElementIsElementType filter to return all types, and WhereElementISNotElementType to return instances, but comparing the two lists does not leave me with the purgeable result. I could compare individual lists of types (i.e. family symbol and family instance), but that... Read more →

LoadFamily and Collector Iteration Performance

Since we are into the topic of family loading performance anyway, after yesterdays discussion on efficient sweep creation, here is another interesting discussion with some useful family loading and symbol filtering benchmarking results and observations by Thomas Jarzyna and an in-depth analysis of the effects of converting a filtered element collector to a .NET collection by Scott Conover: Question: I need to load some family symbols into my project. I have a lot of different families and even more symbols,... Read more →

Sweep Family Performance Enhancement

Now I am back at work again, enjoying the queries coming in from developers, postponing other important things such as my own long-term class and presentation preparations etc. Addicted to helping, that's me. Anyway, here is a piece of doubly good news, in that the developers mentioned below did a good job of helping themselves, in addition to achieving a radical speed improvement from 40 hours down to 3 minutes, i.e. just 0.125% of the original time, to programmatically generate... Read more →

ToElementIds Performance

Conversion of a filtered element collector to an explicit .NET collection of elements or element ids is always costly and mostly avoidable and unnecessary. Before getting to the details of that issue, here is another quick snapshot from our travels to the West European developer conferences. As you either know or might guess, one of the main topics of these is cloud and mobile development, e.g. looking at topics such as the BIM 360 Glue REST API and SDK and... Read more →

Porting an AutoCAD Application

AutoCAD and Revit are very different animals, as we already pointed out a couple of times in the past. Exaggerating just a little, you might say that Revit manages a BIM and ensures its consistency at all times, so there are no exceptions to anything ever, meaning nothing can be overridden. Moreover, almost all Revit geometry is parametrically driven, so there is no way to tweak the model geometry either, except of course by changing the official parameter values. This... Read more →

FindElement and Collector Optimisation

As I recently mentioned, Mikako Harada published a very nice article on programmatically adjusting beam cutback. It was followed it up by a description of some commonly used helper methods to find certain named elements and family symbols in a project. One of them is FindElement, implemented as follows in that post: public static Element FindElement( Document doc, Type targetType, string targetName ) { // Get the elements of the given class FilteredElementCollector collector = new FilteredElementCollector( doc ); collector.WherePasses(... Read more →

FamilyParameter IsShared Property

A long time ago, we discussed a workaround to access the shared family parameter GUID using reflection, more specifically (and obviously) .NET Reflection. If you are new to this, here is an in-depth Code Project article on Reflection in .NET. Now Victor Chekalin, or Виктор Чекалин, ran into this issue as well and presents a much improved solution. Here is the background and our discussion on this: Question: Why does the FamilyParameter class have no IsShared Property, like the Parameter... Read more →

Exporting Parameter Data to Excel, and Re-importing

Did you observe the international talk like a pirate holiday yesterday? I did not, I'm sorry to say. I only became aware of it this morning trying to find some reason why it was so quiet yesterday. Aaarrr! Anyway, here is an update of an age-old sample application, originally created by Miroslav Schonauer for the very first Revit API training classes after the first introduction of the Revit API back in the Revit 2008 timeframe. Miro put together a whole... Read more →

DocumentChanged versus Dynamic Model Updater

Here is an interesting little overview and comparison of possibilities to react efficiently to the addition of certain elements to the database. Two easy ways to achieve this are by subscribing to the unspecific DocumentChanged event, or by registering a more specific DMU dynamic model updater. If you subscribe to an event or register an updater, it is also important to keep in mind to unsubscribe or unregister when you are done with it. We discussed both of these repeatedly... Read more →

Family Usage Filtered Element Collector Performance

Since all access to the Revit database and its elements takes place through the filtered element collectors, it is extremely important to make efficient use of them. We have not looked at that topic for quite a while now. Here is an issue that recently cropped up which illustrates some interesting points. I presented a filtered element sample for creating an XML family usage report which iterates over all the loaded families and launches a new filter for each of... Read more →

The Performance Adviser API

Unbelievable as it may seem, there are still a number of new areas of functionality added in the Revit 2012 API that we have not even got around to covering here yet at all. One of these is the performance adviser. Here is an article on that by my colleague Saikat Bhattacharya from the ADN AEC newsletter. The Performance Adviser API added in Revit 2012 allows developers to execute a set of built-in or custom rules against a given model,... Read more →

Timer Code for Benchmarking

Two topics today: Benchmarking add-ins Hands-on training Benchmarking Add-ins Just like most programming issues, many Revit API tasks can be achieved in numerous different ways. The optimal approach often depends on your individual needs. The only way to find out which one that may be is to test it. In order to test it effectively, you need to measure the results. One of the most important aspects is often the time required, the execution performance. Measuring a short duration of... Read more →

Yet Another Modeless Update

Here is a rather exciting post for me that I spent quite some time on in the past few days. I recently published an updated version for Revit 2012 of my Revit 2011 modeless loose connector navigator and fixed some flaws pointed out repeatedly by Arnošt Löbel at the same time. Please refer to the original post for a full description of the application, since here I am focusing only on the modeless interaction with the Idling event. The main... Read more →

Changing the Type of Many Instances

Did you ever run into a performance problem changing the type of a large number of family instances? Well, is you use the Element Symbol property or ChangeTypeId method to change them one by one, such as we did to set the type of a tag, elbow fitting or cable tray, that may trigger a regeneration within Revit for each call, even if you are using manual regeneration mode and not explicitly asking for a regeneration yourself. Changing a family... Read more →

Extensible Storage Features

Here is a nice hot topic to start off the week. We already talked about the new Revit 2012 API EStorage or extensible storage functionality and presented example code to store a map or dictionary in it. Here are a few other interesting notes and issues related to this which have cropped up, contributed and pointed out by Steven Mycynek: Intended use of EStorage. Handling large amounts of data in EStorage. EStorage is self-documenting. EStorage is object-oriented in two ways.... Read more →

No Multithreading in Revit

I repeatedly hear from developers asking whether multithreading can be used in conjunction with the Revit API. The short answer is no. To our surprise, we just noticed that the Truss SDK sample does demonstrate a use of multithreading. That is an oversight and you should not rely on this working properly. Here is the considered statement of Scott Conover, Software Development Manager of the Revit API, on the current state of multithreading and Revit: "Revit's internals make use of... Read more →

Loading Only Selected Family Types

As you probably know, the Revit API provides two methods to load family types, also known as symbols: LoadFamilySymbol, which loads an individual type, and LoadFamily, which loads the entire family and all the types it defines. Use of the latter method can be quite time consuming and wasteful, especially if you only require a few of the types included. In the past we also discussed a couple of other issues on handling family types, such as creating a new... Read more →

Performant Hardware

I spent all day yesterday in trains, which was unfortunate, since it was the most beautiful Sunday, and springtime is in full bloom. It also forced upon me some unfortunate comparisons of the Swiss and Italian train systems. Needless to say, I arrived later than expected. Still, I ended up happily back in Verona, Italy, where I started seriously learning Italian two years ago, for a repeat visit to provide a Revit API training class to Steel & Graphics srl.... Read more →

Type Filter Benchmark Update

We have come to trust the Revit 2011 API filters to really be the most performant approach to retrieve sets of database elements fulfilling a complex combination of criteria. To reinforce that message, here is another benchmark by Piotr Zurek, who says: While searching for some answers in your blog I have stumbled across an old post where Guy Robinson compared the performance of the Revit 2010 API class filter vs an anonymous method. I found the result really intriguing... Read more →

Filtered Element Collector Sample Overview

The developer conference in Paris went well, and Adam, Partha and I spent a nice day exploring Paris using their wonderful velib bicycle rental system. You pay just one euro for a one-day membership. It allows you to pick up and return a bicycle at any one of the city's hundreds of completely automated and networked rental points. If you return the bike within thirty minutes, it is free of charge. Beyond that time, it costs a euro or two... Read more →

More Kevin Filtering Benchmarks

I caught a germ yesterday in Moscow, maybe travelling on the subway to the office, or at the developer conference itself. I suffered through the night with a pain in the bones of my face and a headache, and yet I was able to catch up on lots of sleep in the end, getting up much later than normal today. The whole morning has also been very unpleasant inside my head, but the rest of me feels fine, and it... Read more →

Autodesk University 2010 Class Materials

I submitted the materials for my three Autodesk University classes yesterday. I checked the enrollment numbers at the same time and was a bit surprised: CP228-2 Optimal Use of New Autodesk Revit 2011 Programming Features, on Revit 2011 API features in general and the Idling event in particular: 154. CP234-2 Exactly What You Want and Faster: Autodesk Revit 2011 Programming Optimization, on optimisation and benchmarking, especially filtering: 135. CP316-3U All Systems Go in Autodesk Revit MEP Programming, an 'Unconference' together... Read more →

Purge Unused Text Note Types

Chuck Dodson of Scott&Goble Architects and my colleague Katsuaki Takamizawa came up with a question on how to purge unused elements from the Revit database, and Harry Mattison from the Revit API development team provides a partial answer: Question: I would like to purge unused elements from the Revit project, such as line types, materials, fonts, etc., especially those imported from AutoCAD. The AutoCAD API provides an IsUsed property for layers and other elements. I have not found any Revit... Read more →

Level Filter Benchmark

Yesterday I published Kevin Vandecar's handout document from his AEC DevCamp presentation on filtered element collectors, and right away an interesting case cropped up which motivated a closer look at one of his samples. By the way, many of his samples are very interesting to have a closer look at, which I plan to do soon as well. For now, let's start off with an analysis of the ElementLevelFilter, based on the following question: Question: A quick question this time:... Read more →

Filtered Element Collectors

One of the most important enhancements made in the Revit 2011 API which is guaranteed to affect almost every single conceivable Revit add-in is the new filtered element collector mechanism, and we have already looked at numerous aspects and examples of using it in various ways. It represents the one and only way to access elements in the Revit database, if you disregard a number of dedicated Document properties providing direct access to specialised collections of various types, which can... Read more →

Model Elements Revisited

Scott Conover responded with a wealth of ideas to yesterday's model element selection discussion, which in turn has gone through numerous previous iterations, so this really seems like an endless theme. Actually it is not even yesterday's, yet, it is still today's. We both wanted to fix it fast. Here are Scott's comments and suggestions: First, on the original solution: IList found = collector .WhereElementIsNotElementType() .WhereElementIsViewIndependent() .WherePasses( new LogicalOrFilter( new ElementIsElementTypeFilter( false ), new ElementIsElementTypeFilter( true ) ) ) .ToElements();... Read more →

Selecting Model Elements

We repeatedly looked at the selection of model elements, and in the discussion on material quantity extraction I mentioned the idea that one possible additional improvement might be to make use of the Category.HasMaterialQuantities property. The topic keeps returning, and now it arose again in a question from Konstanty Seniut. I have updated the answer after the initial posting to add some later notes by Scott Conover, so that they are not missed. To see Scott's notes and explanations in... Read more →

Speed Up Selection

I am now back in Switzerland again after all my various travels, and looking forward to diving into the Revit API in depth again... Here is a really surprising result on how to speed up programmatic selection of a large number of elements, triggered by a question from Joe Offord of Enclos Corp: Question: I have a situation where I'd like to select a large number of curtain panels (over 1000) and add them to my UIDocument.Selection set. These curtain... Read more →

Autodesk University 2010 Classes

Kean's post on AU 2010 classes yesterday reminded me that I might mention my upcoming classes here as well. The catalogues of both physical and virtual classes have been posted to the AU website: My classes are the following: CP228-2: Optimal Use of New Autodesk Revit 2011 Programming Features, a lecture on Revit 2011 API features in general, on Tuesday 2010-11-30 14:00-15:00. CP234-2: Exactly What You Want and Faster: Autodesk Revit 2011 Programming Optimization, a lecture on Revit 2011 API... Read more →

Modeless Loose Connectors

One of the most enthusiastically received samples I presented at the AEC DevCamp conference has also proved a valuable resource since then, in answering various questions on modeless dialogues and ensuring that the Revit application main window becomes the foreground window in certain situations. It demonstrates how we can combine several ubiquitously useful pieces of functionality that we already discussed in the past to implement a homogenous whole. We create an application which collects information from the Revit model and... Read more →

To Regenerate or Not to Regenerate...

... that is the question. We already discussed some best practices concerning the regeneration option. A related topic is how often and when to make calls to the Document.Regenerate method, and how to eliminate such calls when possible. One of the issues we ran into during today's DevLab had to do with performance and elimination of extraneous calls to this method. We also learned that the location curve of a newly inserted family instance does not reflect the true insertion... Read more →

Element Name Parameter Filter Correction

The AEC DevCamp has kicked off here in Boston and it is great to be here with all the fascinating presentations and exciting meetings with colleagues and developers. Somehow, I am also able to keep up with other issues in parallel, and one of them has been a lively discussion with Kevin Vandecar which prompted the presentation of lots of new parameter filter samples this morning. Kevin pointed out that the method I presented in the filtered element collector benchmarking... Read more →

Parameter Filter

AEC DevCamp begins here in Boston today. I started writing this on Sunday evening, before it begins, waiting in the lobby for my colleagues. Later on: finishing it off after a nice dinner with Mikako, Saikat, Partha amd Miro... Later still: posting it first thing in the morning before breakfast... One area that several people have recently been struggling with is the use of parameter filters. As shown by the filtered element collector benchmarking, the use of a parameter filter... Read more →

Regeneration Option Best Practices

Our discussion of the risks of using the manual regeneration option triggered several very interesting comments and suggestions. Here are some important fundamental things to note about the regeneration modes: The automatic mode is not new. It is the mode that Revit has been using all along so far. Developers complained that it is too slow, so we introduced the SuspendUpdating mechanism and now the manual option, providing more and more optimisation possibilities. There is no need to overcomplicate things.... Read more →

Retrieve Stairs on Level

As mentioned in the discussion on selecting model elements, stairs are not represented by an own class in the Revit API, but using the generic Revit Element class instead. They do have a valid built-in category assigned to them, however, which makes it easy to retrieve them from the database and use the generic element and parameter access to retrieve and modify a lot of their data. We also discussed other aspects of stairs in the past, such as listing... Read more →

Retrieving Newly Created Elements in Revit 2011

Here is a largish post which will hopefully keep you happily occupied over the weekend. We looked at the topic of retrieving newly created elements in Revit 2010 last year. Since the method presented there is based on simply retrieving sequential entries from the Revit element collection, and that collection is no longer directly accessible in Revit 2011, I was curious to see whether the approach presented there would still work. To my surprise, with some adaptation, it really does.... Read more →

Collector Benchmark

After all the preparation creating a profiling tool, let us now put it to use on the Revit 2011 collectors, which is one of the areas that has been most heavily reworked in this release and at the same time affects more applications than any other, in fact just about every single one. This has led to a rather huge post for today, but I really wanted to share these important results with just as soon as possible. First of... Read more →

Performance Profiling

I should be preparing my Revit API training in Warsaw, which is coming up next week, and instead I still find myself working on other more interesting topics such as performance profiling at the same time. I hope the training participants will find this interesting as well. New Filtering Motivates Benchmarking The reason why I am so urgently interested in this right now is that the Revit 2011 API provides a whole new filtering API, i.e. for extracting certain specific... Read more →

Duplicate Mark Values

We already discussed the issue of door marks and implemented the Building Coder sample command CmdListMarks to demonstrate listing and modifying them programmatically. Here are a couple of additional questions that came up recently in this context from Dave Echols of Hankins and Anderson, Inc. which led to some important hints on performance and exception handling: Question: We have some large Revit models that have thousands of errors due to duplicate mark values. On several of these, we have cleaned... Read more →

Nested Family Utility Methods

Nested families seem to be a recurring topic right now. We just recently discussed how to test whether a family instance in a project file is nested inside another, and before that we addressed nested instance geometry and creating a nested family. The first place to look for information on using the Revit API in the context of families is the overview of the family API with the associated labs and the materials and recording of the webcast we presented... Read more →

Select Model Elements 2

We already had several stabs at the topic of selecting all model elements, i.e. all elements in a Revit BIM which contribute to the building geometry. Their main characteristic is that they have a non-null geometry which is visible on the graphics screen and really contributes to the physical building model. Unfortunately, some elements which are not part of the building itself also have valid geometry and need to be eliminated. The latest version of the code that we presented... Read more →

Revit Family Creation API Labs

The handouts and presentation for my Autodesk University family API session are finally done, as well they should be, since they are due to be submitted by today. The last part I worked on was to add more documentation on the family API labs to the handout document. I think this overview will be of interest here as well. The family API labs were originally created and documented by Mikako Harada, the ADN AEC workgroup lead, so all of the... Read more →

Three Coding and Performance Hints

We received three interesting and important coding and performance hints from Piotr and Guy Robinson on the post on Linq yesterday. I find them too important to leave them dozing away in the comment section, so here is their promotion to post status: Use auto-implemented properties to simplify the helper class code. Use ParametersMap instead of looping over all element parameters. The .NET Framework 3.5 SP1 is significantly improved over .NET 3.5. As Piotr pointed out, auto-implemented properties are a... Read more →

Language Integrated Query Linq

The Language Integrated Query or Linq is a .NET Framework component that adds powerful native data querying capabilities to .NET languages. Here is a contribution by Joel Karr of Environmental Systems Design, Inc on this exciting topic, demonstrating how it can be used to achieve huge performance improvements when analysing large Revit models. Using LINQ to Query Here at Environmental Systems Design, www.esdesign.com, we have seen that a simple task in Revit, such as changing a single parameter of an... Read more →

Category Comparison and Model Elements Revisited

This is a follow-up to two previous posts, on category comparison and the selection of model elements. Regarding the category comparison, we discussed the fact that categories cannot be compared directly, and one should use their element id instead. We also underlined that every category comparison should be made language independent by using the built-in category enumeration and not comparing the localised category names. The analysis of the model element selection examined how to eliminate the preview legend components from... Read more →

Imports in Families

I will have left on vacation once again by the time this is posted. In case you wonder why I am on vacation so much, the trip to Italy in March and the wonderful experiences I had there were actually to use up last year's contingent. Now I am getting started on this years', going off on a climbing and driving trip to southern France with my two sons Christopher and Cornelius, especially to the Provence and Avignon to visit... Read more →

Parameter Binding Performance

Here is a short but important question that has come up repeatedly concerning the performance of parameter bindings. Question: There is a big problem in the early versions of Revit 2009 with the performance of the Document ParameterBindings property, for example in the last line of the following code: Application app = commandData.Application; Document doc = app.ActiveDocument; BindingMap bindingMap = doc.ParameterBindings; The last statement takes a huge amount of time to execute, in the order of minutes. Are there any... Read more →