The Building Coder

Nested Lighting Fixture Instances

We already looked at a couple of aspects of nested family instances, such as access to nested instance geometry, creating nested families and determining whether a family instance is nested. Now Joel Spahn of Lighting Analysts, Inc. submitted a comment on the nested family utility methods raising a new question related to nested lighting fixtures, efficiently resolved by Harry Mattison of the Revit development team: Question: I have adapted this code to extract nested family instances and it works beautifully.... Read more →

Use of NewTakeOffFitting on a Pipe

I presented an example of using the NewTakeOffFitting method on a duct a while back. The original question, however, was actually related to inserting a break into a pipe. That turned out to be a bit more tricky. This was also discovered by Kailash Kute, who posted a whole series of comments on the topic. I will herewith reiterate my first answer to him and post the code that I had working to see whether that will help us move... Read more →

ASHRAE Viewer Plugin of the Month

We recently published our first ever Revit plugin of the month, for March, Adam's Room Renumbering add-in. Now the second one is already available on Autodesk Labs as well, for April, an ASHRAE Viewer for Revit MEP by Martin Schmid of Autodesk's AEC Industry Success team: The download includes ready compiled versions for both Revit 2011 and 2012, a complete user manual, and full source code, so you can use it as is, tweak it for your specific needs, or... Read more →

Distinguishing MEP Element Shape

Normally, when given a family instance, you can access the family name to obtain some information about it. For Revit MEP ducts, however, the duct shape is determined by an internal system family whose name is visible in the user interface but is not accessible through the API. For instance, with ducts, you cannot access the family of a round duct. In the user interface, it appears to belong to a family named "Round Duct", but in fact this built-in... Read more →

Create a Pipe Cap

Things have been a bit hectic for me in the last few days, with several complex cases to solve. I also suddenly and unexpectedly had to find out how to apply for a visa to Saudi Arabia, which is a kind of interesting process. Apparently, you start out with the inviting company in Saudi Arabia, which has to issue an invitation letter. This has to include a reference number, for which a form needs to be filled in and submitted... Read more →

Use of NewTakeOffFitting on a Duct

Here is a simple question on how to create a new MEP takeoff on a duct using the NewTakeOffFitting method: Question: I have a duct in my Revit MEP model and I want to create a takeoff fitting at its midpoint. I see that the method NewTakeOffFitting takes two arguments, a connector and an MEP curve, and returns a new family instance. My question is: How can I create the connector and curve? Can you show me some code on... Read more →

Unit Conversion and New Blogs

Quite a while back, I published a unit conversion utility for Revit 2010. Let's take a fresh look at that, and also at a couple of new Revit blogs. We discussed a couple of other issues related to units since then, such as the unit suffix and ProjectUnit SDK sample and a look at voltage units. The latter also includes an overview of some other unit related posts. Anyway, Rod Howarth picked up on the unit converter utility and ported... Read more →

Setting Duct Width and Height Requires Regeneration

Whenever you have a problem modifying or querying the model with your Revit plug-in, one of the first things to check is always your regeneration mode. If you are using the manual regeneration option, you need to check whether you possibly omitted a required intermediate regeneration call. It seems that there can never be enough reminders of this. Here is another case at hand: Question: I am sizing rectangular duct fittings through the API, and I noticed that the different... Read more →

Ray Tracing to Place Family Instance

Jeremiah Farmer of Land F/X recently presented his solution for placing a site component on a topo surface. One important issue in addition to the information presented there is that the family instance insertion point needs to be located on the surface. One way to find a suitable point is to use the Revit API method FindReferencesByDirection to shoot a ray through the model to determine a suitable point, i.e. the intersection point between the ray and the surface. If... Read more →

Project Vasari API

I mentioned the Autodesk Project Vasari last week, and the first question from Fernando Malard was whether it also provides an API. The question makes a lot of sense on this blog, since everything we discuss here is related to the Revit API. I thought Vasari would be an exception. Surprisingly, this is not the case. Ritchie Jackson asked the same thing, and received the following very satisfying reply from Matt Jezyk: Question: Vasari has the potential to be a... Read more →

Connector Direction and CreateAirHandler Sample

Here is an update to the CreateAirHandler SDK sample provided by my colleague Greg Wesner together with an interesting analysis of MEP connector directions. We looked at various aspects of MEP connectors several times in the past: The difference between the family connector elements and the project connector class. Enhancing RevitLookup for MEP, previously known as RvtMgdDbg. Connector orientation. Retrieving MEP elements and connectors. Modeless loose connector navigator. The CreateAirHandler SDK sample shows how to create an MEP air handling... Read more →

Autodesk Project Vasari

Autodesk Project Vasari is an easy-to-use, standalone design tool with analysis capabilities available via the cloud, built on the same technology as Revit, aimed at architectural designers and building energy analysts. It is focused on conceptual building design using both geometric and parametric modelling and supports performance-based design via integrated energy modelling and analysis features. It is compatible with Revit in that files created with it can be opened using Revit 2011, and vice versa. There are some limitations in... 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 →

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 →

Flex Duct Start Tangent

Still zipping around in Pattaya with my brother Marcus, and still blogging a bit now and then as well ... Here is a suggestion for a workaround to specify the start and end tangents of a flex duct or pipe that evolved through a recent exchange of comments with Zhu XiaoMeng: Question: In the Revit application UI, I can create a FlexDuct properly with the start tangent of the Hermite curve in a reasonable direction. But when I create a... Read more →

Populating a Data Grid View

By the time you read this, I will be gone on the first of a series of holidays this summer. By the way, for that reason, don't expect any answers to comments for a while. I left the computer at home this time! I posted this in advance to ensure you have something worthwhile to chew on during my absence. This is another stepping stone towards implementing Martin Schmid's proposal to display and navigate through all unconnected MEP connectors in... Read more →

Retrieve MEP Elements and Connectors

My colleague Martin Schmid recently asked about the feasibility of listing all unconnected connectors in a Revit MEP model. To do so, the first step is to retrieve all the elements that can potentially have connectors, and then examine their connectors to see which of them are not connected to a neighbouring element. We looked at many examples of using the filtered element collectors in the past. A summary of previous posts is given in the discussion on parameter filters,... Read more →

MEP System Creation

Yesterday was a great day here at the AEC DevCamp, except that I was unable to attend a session held by Scott Conover presenting material by Arnošt Löbel, since it collided with my own. I enjoyed myself in the latter, anyway, and so did the audience, it seemed. Meanwhile, life outside DevCamp is also continuing, and here is a very interesting case submitted by my old friend Thomas Wegener and handled by Joe Ye on Revit MEP system creation. Our... Read more →

Voltage Units

The last day before DevCamp! I am happy to note that the articles on grabbing a webcam image and displaying it on a Revit element face were so popular ... I will be demonstrating that and other samples using the Idling event and modeless dialogues at DevCamp. Meanwhile, here is an interesting little item that my colleagues Jorgen Dahl and Martin Schmid (who by the way published a book on AutoCAD MEP 2010) dug up, another nugget of information on... Read more →

Voting Open for AU 2010 Sessions

Shamelessly copying Kean's lead, here is an overview of the classes I have submitted for this year's Autodesk University: Session ID 5977 – Optimal Use of New Revit 2011 Programming Features A 60 minute lecture teaching everything you need to know about the new Revit 2011 programming features and how to use them, with many code examples, making use of all new API features in all types of Revit add-ins. We also present the one and only complete overview of... Read more →

Cable Tray Orientation and Fittings

In the overview of the Revit MEP 2011 API, I mentioned that new elements have been introduced to represent cable trays and conduits. We already had a look at the creation of new conduit elements in the pipe to conduit converter. The creation of cable tray elements is equally simple, making use of the static Create method on the CableTray class. This is another example of the new element creation paradigm instead of the creation document classAutodesk.Revit.Creation.Document, a second generation... Read more →

Solar Radiation Technology Preview

The solar radiation technology preview for Revit 2011 is now available. It helps understand and quantify solar radiation on the surfaces of a conceptual building model. This can help make informed design decisions about building shape, orientation, and shading strategies early on when changes are least expensive. A new version was just released, including many improvements and closer inntegrated in the Revit user interface: One aspect of interest to application developers is that this plug-in is written entirely using the... Read more →

The Revit MEP 2011 API

Revit 2010 and 2011 both put a strong focus on the development of Revit MEP, both from an end user and a programming point of view. The API features provided with Revit 2011 provide important new functionality for Revit MEP add-in developers. Of course, the entire platform API features such as dynamic update, analysis visualization, user interface integration, selection mechanism, transactions and other enhancements are applicable and extremely useful to MEP add-ins as well. A number of additional MEP specific... Read more →

Pipe to Conduit Converter

I am pretty busy right now, both with day-to-day work answering cases and preparing training material, and also preparing for upcoming events. These include: Revit Programming Webcast on May 20 (register). DevCamp conference on June 7-9. DevLabs in Waltham, USA, on June 10-11 (register). DevLabs in Munich, Germany, on June 21-25 (register). Autodesk University ... still far away in the future, but some preparations already have to be made. Lots and lots of vacation this summer! Due to all that... Read more →

Revit 2011 API Webcast

Here is a last-minute reminder to register for the Revit 2011 API webcast that we are holding on Wednesday April 21st, in eleven hour's time. To register, you can visit the Autodesk Developer Network (ADN) DevTech API training schedule site, filter for 'Revit 2011 New APIs', and click on the register link. This webcast is open to all developers, regardless of ADN membership. Sorry for the late notice, I was too caught up in the discussion on the regeneration option... Read more →

MEP Hangers

We repeatedly touched on various topics related to the Revit MEP API. Here is another little item that is a bit more out of the way, some background information on MEP duct and pipe supports, also known as hangers. Question: In the description of the MechanicalEquipment class, the Revit MEP API help says that "The Mechanical Equipment object can only be queried in Autodesk Revit MEP." I would like to add supports to ducts and pipes. Could you please tell... Read more →

Connector Orientation

I am still looking through all the interesting cases my colleagues dealt with during my absence. Here is another one handled by Joe Ye on the width and height orientation of a Revit MEP connector: Question: Given an Autodesk.Revit.DB.Connector object, is it possible to know where the height and width dimensions are relative to the Connector.CoordinateSystem? The width and height directions do seem to be aligned to either the coordinate system X or Y axis, but not consistently one way... Read more →

Insert Face-Hosted Sprinkler

In between the series of background information from Scott's Autodesk University presentation on analysing building geometry, let's have a look at another example that combines a little bit of geometric analysis with other issues. This example is from a case handled by Joe Ye and exploring how to insert a face-hosted sprinkler into the model. A family instance is used to represent the sprinkler, so we presumably need to make use of one of the overloads of the NewFamilyInstance method.... Read more →

Rectangular Duct Corners

In between the series of background information from Scott's Autodesk University presentation on analysing building geometry, let's have a quick look at a practical application. This is an MEP-specific issue on how to determine the corners of a rectangular duct. One approach to determine this information is to perform the following steps: Analyse the duct geometry. Extract its solid. Iterate over the faces. Select the face containing the rectangular connector. Determine its four corners. We explored the geometry of various... Read more →

UK Electrical Schedule Sample

Here is my final Christmas present and last post of the year. Over the next few days, I will do my best not to answer any email or comments :-) This final gift before I leave is from Simon Jones, Technical Sales Manager of Autodesk UK. Simon has been strongly and enthusiastically involved in all things AEC related for several decades now and was maybe the main early driving force of the use of AutoCAD in the architectural realm in... Read more →

AU Virtual free for ADN Members

Kean Walmsley just announced that a free Premier Pass to Autodesk University virtual is available for members of the Autodesk Developer Network. Please join us there. We are presenting at both AUv and the non-virtual AU: Kean's F# sessions. AutoCAD-related AU and AUv sessions. The Revit Family and MEP APIs. I am looking forward to seeing or hearing from you in the next couple of days! Read more →

Revit API Flavours

Maher raised an interesting question regarding the different flavours of the Revit API: Question: I have a few questions on Revit MEP, Arch, and Structure in general. What are the major highlights of each API? I downloaded the SDK and tried to read through. But could not get my head around it as it is very overwhelming. It would be great if you could post something in the difference between these three flavours both in terms of API and in... Read more →

AU 2009

These days I am pretty occupied with the preparation of my sessions for Autodesk University 2009: CP308-2 All Systems Go in the New Autodesk Revit MEP API CP9118-1 The New Autodesk Revit Family API: Everything is Relative The Family API one is a virtual class which requires special preparation, since it is being recorded and broadcast worldwide for Virtual Autodesk University. As Rick Graham pointed out, virtual AU was created for those who are not able to make it to... Read more →

System Versus User Family Category

Here is a simple question and suggestion on classifying categories into built-in system versus user defined. Question: Given an arbitrary element, how can I determine whether it belongs to a system family as opposed to a user-defined family? I thought I might look at its category, but how can I see whether that is system-defined? For example, I see that a duct has a category id of -2008000. Can I depend on the fact that this category id value is... Read more →

Modeless Pressure Drop Tool

This weekend I went with a couple of men friends to spend two days together in Arcegno near Locarno. One afternoon we went climbing together in Ponte Brolla at the end of the Maggia Valley. We did some very easy climbs, because some of us were absolute beginners, Jimmy (4b), Ostro (5a), Mekka (4c), and Muckel (5b), wonderful slab climbing on the big, clean, warm sloping rock face. The next day we went on a hike from Aurigeno, a few... Read more →

Getting Started with the Revit 2010 API

I am back again from a great vacation in Italy which I mostly spent outdoors camping, swimming, cooking, and drinking cappuchino. Yesterday was the Jeûne Fédéral holiday (French) in Neuchâtel. I used that to make a first pass through my overfull email inbox. Meanwhile, here is a quick summary and overview of the material we have put together so far for getting started with the Revit 2010 API. Question: Do you have any updated information similar to the getting started... Read more →

The Revit MEP API

By the time you read this, I will be away happily on a one-week vacation in Italy. I hope you and the blog manage yourselves and behave well until I return. I scheduled some items to be published in my absence, though. In previous posts, we already had a look at the new MEP-specific API features in Revit 2010 and the classes involved in defining and representing MEP connectors in particular. On August 27th 2009, we held the first webcast... Read more →

Revit MEP API Webcast

Here is a last-minute reminder to register for the Revit MEP API webcast that we are holding on Thursday August 27th. You still have 36 hours time until it begins, starting now. To register, you can visit the ADN or Autodesk Developer Network ADN DevTech API training schedule, filter for Revit MEP API, and click on the register link. This webcast is open to all developers, regardless of ADN membership. I am still very busy preparing the material :-) Read more →

Fixing RvtMgdDbg for MEP Connectors

Still working on preparations for the MEP webcast mentioned last week, I notice that RvtMgdDbg is having trouble displaying the connectors on electrical components, throwing an exception saying Angle is available only for connectors of DomainHavc and DomainPiping. The method I describe here to fix this problem can be used by anyone who runs into a problem with RvtMgdDbg. It is not limited to the case of MEP connectors, and intended more as an example and a how-to on how... Read more →

MEP Sample Ribbon Panel

I am preparing our upcoming Revit MEP API webcast to be held on Thursday August 27th. To register, you can go to the Autodesk Developer Network (ADN) DevTech API training schedule and filter for Revit MEP API. One thing I did today was to update our MEP sample external application from the Revit 2009 menu-based user interface to a 2010-style custom ribbon panel. Here is the code for the AddMenu method that was being used in Revit 2009 to create... Read more →

Electrical Settings and Lighting Fixtures

Here are two recent questions on electrical settings of distribution systems and family instances for lighting fixtures handled by Saikat Bhattacharya and Joe Ye, respectively. By the way, this is a special occasion, namely the 200th post to The Building Coder. I will resist the temptation to declare this as a birthday post like I did post number 100, because the first real annual birthday of The Building Coder is coming up quite soon now anyway, and we don't want... Read more →

External Command Replay

Matt Mason of Avatech Solutions pointed out a few important items related to the preceding post on replaying a journal file: One topic that you did not cover – using the journal file with Revit external commands. Here are some things that I've noticed in the past: If your external command has dialog boxes, your application will freeze if Revit is being driven by a journal. The alternative to this is to use the JournalData StringStringMap in the ExternalCommandData which... Read more →

Harvard Energy Model Survey

Here is an invitation to a survey on the use of building energy models during design, construction and operation. It is being carried out by the Graduate School of Design at Harvard University (GSD) in collaboration with the Harvard Office for Sustainability (OFS) and addressed to building owners, architects and energy consultants to better understand: who on the design team owns and gets access to the energy model of a building, what role the model currently plays during building design... Read more →

Space Adjacency

We looked at the topic of room and wall adjacency a while back. Martin Schmid now implemented a nice little related utility to check adjacencies between spaces. It demonstrates a beautiful use of the new Space.IsPointInSpace method. Here is an example of the kind of situation he is interested in: The aim is to obtain a list of all adjacent spaces from this model. Martin added a new external command CmdSpaceAdjacency to The Building Coder sample application to analyse and... 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 →

Volume Computation Enable

We discussed abstract volume computation of a convex hull or cloud of points last week. Revit can also compute certain volumes, of course, for instance the volume of rooms. However, this functionality is not automatically enabled. To switch it on you need to set a certain toggle called VolumeComputationEnable on the document settings volume calculation options. Unfortunately, there is a slight issue with the API documentation on this property ... Question: When I try turn on the value of the... Read more →

Export Family Instance to gbXML

The Green Building XML Schema or gbXML was developed to facilitate the transfer of building information stored in CAD building information models, enabling interoperability between building design models and a wide variety of engineering analysis tools. It has been widely adopted by leading CAD vendors and is on the road to becoming a de-facto industry standard schema, so we obviously see more and more application developers interested in using and supporting it, leading to questions such as the following one.... Read more →

The Revit MEP 2010 API

We already presented an analysis of the MEP connectors in Revit 2010, but a general introduction to the MEP-specific API is still missing. Or was, until today. Question: What can I do with the Revit MEP API? What's new in Revit MEP 2010? Are there any additions or enhancements specifically for the MEP flavour? Any new content? Answer: The Revit 2010 API has been strongly enhanced with new MEP-specific features. The main feature of the RME API is to provide... Read more →

MEP Connectors

We had an internal discussion on the relationship between the different API classes involved in defining connectors in Revit MEP which I thought might be of general interest as well. Question: What is the difference between the Connector class versus the DuctConnector, PipeConnector and ElectricalConnector ones? I know one of them is used in the context of family documents only, and the other one is in project context. But what is the main difference between them? Answer: In Revit MEP,... Read more →

Omni Class Numbers

Revit 2010 supports OmniClass codes. The Revit Architecture help provides the following background information on these codes in the section on Preparing Content for Sharing with Autodesk Seek, which is currently only available in the English edition: OmniClass is a new classification system for the construction industry. The Autodesk Seek website uses codes from OmniClass Table 23 to filter and identify shared content. A code consists of an OmniClass number and title. If an OmniClass code is not already assigned... Read more →