The Building Coder

Store Project Data

We recently discussed storing structured data in a Revit file, and received a number of very helpful additional comments on the topic. To store custom application data in a Revit project, one needs to attach a shared parameter to some Revit elements. As we have seen in the discussion on model group shared parameters, almost any element can be used to host the shared parameter. Here is a common related question: Question: Where can I store project-wide information in a... Read more →

API Wish List Survey Reminder

Here is a last minute reminder that the Revit API wish list survey that I already pointed out in a previous post will be closing this Friday, July 31st, 2009. Thank you very much to all of you who have already completed it! The number of participants has increased significantly since last year, thanks to you. Just to show you that the results of this wish list survey really do have a strong influence on the API development, here is... Read more →

Porting from C# to VB.NET

Yesterday, we mentioned Kean Walmsley's recent post on converting between C# and VB.NET. In response to the closely related frequently asked question on porting the Revit SDK samples provided in C# to VB.NET, here is an exhaustive study of the topic by Adam Nagy. Question: I'm looking at the Revit SDK samples, but many of them are in C#. Since I am a VB.NET programmer I'd prefer to use a VB.NET version. I tried to convert them myself but ran... Read more →

A .NET Language Learning Resource

Since all Revit API programming is based on .NET, and the most accessible programming languages for creating .NET applications are C# and VB, we are occasionally asked how to get started with these. While we discussed the resources available for getting started with the Revit API itself, there is also a need to learn a .NET programming language in order to make efficient use of it. Here is an enthusiastic endorsement from Jack Foster for some VB.NET training material. Jack... Read more →

Integration with a Database or ERP System

A while ago, I published Miroslav Schonauer's popular high-level overview of Revit and database integration. Here is an additional useful note from Anthony Hauck on this topic: Question: How can I integrate Revit with an ERP solution or an SQL database? Answer: Revit information can be exported to an ODBC-compatible database. ODBC export is a native feature of Revit. The Labs posting RDBLink demonstrates a similar capability using the API, with the additional feature of being able to change some... Read more →

Debug Geometric Form Creation

Here is a useful hint on debugging the generation of geometric shapes from Harry Mattison. Question: I am trying to create multiple swept blends in a family document. The first call to FamilyCreate.NewSweptBlendForm() succeeds, but the second call is failing with the following exception: Answer: For problems like this I suggest commenting out the code that creates the form so that the command creates only the lines being used to create the form. Then you can run the command, verify... Read more →

Store Structured Data

After yesterday's exciting and successful Revit Family API webcast, here is a complete and mature solution to a frequently asked question that I mulled over for some time. Question: I read your post on creating a shared parameter on the model group, which also shows how I can store arbitrary application data on almost any Revit element. However, due to the way that Revit parameters are defined, the type of the data item contained within the parameter is limited to... Read more →

Revit Family API Webcast

Here is a last-minute reminder to register for the Revit Family API webcast that we are holding tomorrow, Thursday July 23rd. You have 25 hours time until it begins, starting now. To register, you can visit the Autodesk Developer Network (ADN) DevTech API training schedule site, filter for Revit Family API, and click on the register link. This webcast is open to all developers, regardless of ADN membership. Read more →

Scale a Curve

Now let us get back to really practical things again, after the practical notes on impractical things, and the more or less practical boot camp note. Question: I have a CurveArray object containing data defined in inches. Now I need to scale it to feet in order to feed it into a Revit API method to create an extrusion. How can I perform this scaling operation? I would obviously prefer not having to rebuild the entire CurveArray. How does one... Read more →

Revit Boot Camp on Mac

Following up on the practical notes on impractical things, here is one on a practical thing as well: Autodesk is now officially supporting Apple Boot Camp for users of AutoCAD, 3ds Max, Inventor and last but not least the three flavours of Revit. Boot Camp is a component of the Mac OSX operating system that enables customers to run Windows on the Mac. See www.autodesk.com/mac for more general details and this FAQ for some frequently asked Revit specific questions and... Read more →

Practical Notes on Impractical Things

I just learned that the two introductory images presented in the article on the Revit form creation API came from Zach Kron, whose blog Buildz presents lots of interesting 'practical notes on making impractical things' in Revit. Here is a pointer to a completely different kind of practical note on another blog: Disable Auto Setback in Framing Template Several developers have been struggling with some of the hard-coded Revit behaviour. Miroslav Schonauer just pointed out that he and Sarah Capes... Read more →

NewLineLoad

In Revit Structure, a new line load is created using the NewLineLoad method. It provides four different overloads, which we wish to explore here in a little more detail: NewLineLoad(XYZ, XYZ, XYZ, XYZ, XYZ, XYZ, Boolean, Boolean, Boolean, LineLoadType, SketchPlane): unhosted line load using data at two points. NewLineLoad(XYZArray, XYZArray, XYZArray, Boolean, Boolean, Boolean, LineLoadType, SketchPlane): unhosted line load using data at an array of points. NewLineLoad(Element, XYZArray, XYZArray, Boolean, Boolean, Boolean, LineLoadType, SketchPlane): hosted line load using data at... Read more →

Revit Form Creation API

Here is an overview of the Revit form creation API written by Saikat Bhattacharaya. The form creation and conceptual design API can be seen as a subset of the new Revit 2010 family API. It includes new point and curve objects, form making tools, and new surfaces that can be divided, patterned and panelised. You can use it to create schematic studies for curtain system designs and structural framing layouts, and even apply real curtain panels to your form with... Read more →

Language Independent Category Access

I recently discussed category comparison, and I keep stressing the importance of keeping the application implementation language independent as far as possible. Jiri Smerak of Ing.-Software Dlubal GmbH now uncovered a situation in which due to a localisation issue the language independent category comparison is in fact the only way to access certain categories in the German version of Revit Structure. The issue has to do with the following built-in categories: OST_LoadCasesLive OST_LoadCasesRoofLive OST_LoadCasesSnow OST_LoadCasesWind When trying to access these... Read more →

API Wishlist Survey

The Summer 2009 Revit API wishlist survey is now ready and will remain open until July 31st, 2009. Please take the time to fill out the survey. The engineering team uses the feedback you provide to prioritise our API development efforts. This is a great chance for you to have a direct impact on the direction we take in exposing APIs to our products. Kean Walmsley lists the wishlist surveys for other Autodesk products and offers to send you a... Read more →

Think Big in Revit

A couple of cases dealing with issues concerning small dimensions in Revit were recently raised by Toste Wallmark of Tecton Limited and Henrik Bengtsson of Lindab: Minimal length required when calling NewLineBound. Minimal possible family component dimension. Minimum scaling factor for annotation family symbol. Minimal Length in NewLineBound Question: I have discovered that NewLineBound throws System.ArgumentException "Value does not fall within the expected range" when the values are close or very close. Is that an expected behaviour in this case?... 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 →

Journal File Replay

In spite of pretty mixed weather I went on a climb in the alps with my friend Robert on Saturday, the route Kurze Kombination (4c) on the mountain Schmalstöckli (2012 m) close to the Lidernenen Hütte. Here I am after the climb, just below the summit: And this is Robert on the summit itself: We would made another climb on the same mountain if the weather had not been pretty grey and moist. Anyway, now it is Monday morning, and... 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 →

Retrieving Newly Created Elements

The day before yesterday, I demonstrated the use of the Mirror method. Henrik Bengtsson of Lindab immediately came back with a question on this. Funnily enough, the reason I quickly posted the article the day before yesterday was because someone completely different asked the exact same two questions as Henrik in the exact same sequence. There seems to be some kind of morphogenetic resonance going on among Revit developers. Anyway, here is Henrik's question: Question: The mirror command works all... Read more →

View Sketch Plane

Some views provide a sketch plane, others do not. In particular, the section views do not. Here is a little exploration into this subject prompted by the following question from Toste Wallmark of Tecton Limited: Question: I'm trying to get the SketchPlane property of currently active view, which is a section view. However, it returns null. Do I need to manually create a sketch plane for section views? Other types of views, like floor plans, do correctly return a SketchPlane... Read more →

Mirror an Element

We already discussed transformation of elements using Move and Rotate. Here is a question regarding the related method Mirror that also deserves attention: Question: I am trying to mirror a family instance element using the X axis as the mirror line. I am creating a new line using the NewLine method and then supplying a reference to that to the Document.Mirror method, but this is causing Revit to crash. The Reference property of my line is always null. I am... 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 →

Revit 2010 Web Update 1

The Revit 2010 Web Update 1 is now available from the usual places: Revit Architecture Revit Structure Revit MEP Click on the Product Download link on the left hand side. Here are the detailed Revit API enhancements included in this update, available in all three flavours: Suppressed Revit inaccuracies warnings during transaction when generating geometries using massing API. Associated LinearArray's NumMembers property with Family parameter. Dissociated FamilyParameter from Label property of BaseArray and Dimension. Provided a tool to update reference... Read more →

DWG and DWF Family Creation

Here is another question on family creation, this time not regarding parameters, but the geometrical content and reuse of existing geometry. Revit is a strongly parametric system, and the Revit family management obviously also. However, if one happens to have important predefined static geometry for certain components, that can be reused as well. It is of course a shame to be using static, non-parametric geometry in an environment with such powerful support for parameterisation. In some cases, however, reusing pre-existing... Read more →

Get and Set Family Category and Parameters

I am receiving a lot of questions about parameters in family documents, so I will be posting several solutions in this area in the next few days. The first one is short and simple and suited for a rapid Saturday post. There is so much news coming that I do want to cram it in right away. This is a question from Jose Fandos of Andekan LLC: Question: How can we get and set the family category and the family... Read more →

Prompt the User for Pinning and IFC Export

We recently touched on the topic of IFC export and the lack of API access to this functionality. Another property that the Revit API also does not provide write access to is the Element.Pinned property. In both of these cases, however, write access is provided through the user interface, and it is possible to programmatically read the current state. Therefore, an application can determine the current state and prompt the user to execute the required action if necessary. While it... 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 →