The Building Coder

Creating a Non-rectangular Slab

Here is a question raised and answered by my colleagues Katsuaki Takamizawa and Phil Xia on creating and editing a slab. Some related topics that we already discussed are related to the analysis of the geometry of existing slabs, e.g. the slab boundary and its side faces, explorations of the geometry of other elements, the eave cut property of roof slabs, and how to edit a floor profile. Now let's look at this generic slab issue: Question: In the user... Read more →

Obfuscation Tools

We already explained the need for and basics of obfuscation, and yet developers I meet are often still surprised to discover how easy it is to decompile their .NET application and obtain the original source code back from the released .NET assembly DLL. We can add new information on this topic and present details on some available tools now, because Greg Wesner of Autodesk kindly agreed to share his personal experience and research results using obfuscation with Revit applications: First... Read more →

New Sweep and References

Here is a question posted by Mike Cotreau of Langan Engineering & Environmental Services on how to create a new sweep using a reference array, which provided a welcome opportunity to explain a little about the use of references in the Revit API: Question: I want to use the NewSweep method to create a 3D curb line that follows along a path of 3D points. The NewSweep method can be invoked in two ways, one uses a ReferenceArray and the... 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 →

Autodesk Search Beta

We recently mentioned two new online search possibilities, the availability of online help for the Revit product and Rod Howarth's customised global Revit API search. Here is another note in the same vein: Autodesk Search Beta is now available and provides a number of new capabilities including: Type-ahead. “Did you mean...” Filter by publish date, site source, etc. Expanded search scope covering discussion forums, blogs, online product documentation, community sites and the Autodesk channel on YouTube. Please check it out... Read more →

Shared Parameter Visibility

Here is an interesting question and a workaround for a problem accessing the visibility property on shared parameters, raised by Jon Smith of Construction Industry Solutions COINS: Question: We need to be able to tell if a parameter is visible or invisible, so we can honour that setting in our own interface and not display it if set to invisible. We try to do this as follows: ExternalDefinition externalDef = param.Definition as ExternalDefinition; if( externalDef == null || externalDef.Visible )... Read more →

Happy Building Coder Birthday!

The first Building Coder post was published one year ago, on August 22nd 2008. We celebrated an intermediate birthday with the hundredth post in February 2009. Today is the first real annual birthday and The Building Coder has now reached the ripe old age of one. I am celebrating with a nice cup of cappuccino. I actually add a drop of cream to mine. To further celebrate, I will say no more after 207 posts so far. Read more →

Library Paths

Here is a question posted by Edgar on how to modify the application options library paths: Question: I'm having trouble updating the Revit options for library paths. I'm not sure what I'm missing to update back to the database. Answer: Since the library paths managed by the LibraryPaths property on the Autodesk.Revit.Options.Application class is a StringStringMap, this question is mostly on how to extract, add and modify data in such a collection. A StringStringMap is simply a dictionary mapping a... Read more →

Deleting a Shared Parameter

Here is another question handled by Joe Ye, on removal of shared parameters. Question: I'm creating a shared parameter and adding it to a parameter group. I then bind it as an instance parameter. I would like to be able to test and remove the binding if a parameter of the same name exists. For instance, I am creating a parameter called XYZ_TEST_PARAMETER. If I run the code twice, I end up with two parameters with the same name. I... 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 →

Bottom Face of a Wall

We already went into quite a bit of detail analysing the geometry of walls and other elements, but the topic keeps cropping up again anyway. An overview of the preceding posts on this topic is given in the discussion of cylindrical columns. Here is a case handled by Joe Ye which I thought might complement the previous posts on this topic, since it is so simple and minimal. Question: How can I find the bottom face of a wall? Answer:... 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 →

DWG Export Filename

Here is a question handled by Joe Ye that I thought might be of general interest. It makes use of the Revit SDK sample ImportExport converted to VB.NET. We mentioned the issue of converting Revit SDK samples from C# to VB in one post, and Adam Nagy later presented a more complete port. Question: I am making an application to export Revit views to DWG files. I used the ImportExport sample converted to VB.NET as a basis. I am having... 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 →

The Revit Family API

Here is a rather lengthy and rich post to start off the week, describing the new family API introduced in Revit 2010 and including both an overview and in-depth information. These are the main topics covered: Creating a Family through the User Interface. Creating a Family Programmatically. Family API Samples in the Revit SDK. Family API Labs: Creating an Example Family. Family API Webcast and Materials. The text presented here is also a script for the Revit Family API slide... Read more →

Roof Eave Cut in AutoCAD Architecture and Revit

Here is a case that is interesting in its own right, or rather two separate cases and a comparison between the two. The issue is the programmatic setting of the roof eave cut property in AutoCAD Architecture and Revit, respectively. One interesting aspect is the similarity and differences between the two solutions. First of all, here is the original question, addressed at ACA: Question: I am having difficulty accessing the edges of a RoofSlab entity. I am programming in C#.... Read more →

Online Revit API Help

On Monday, we pointed out that the Revit product help is available online. Rod Howarth responded with a comment mentioning his very useful custom Google search for global online Revit API help. Rod also published a blog post providing some background info on his centralised search engine. Many thanks to Rod for providing this powerful time-saving tool! Read more →

Unit Conversion

Here is a useful and instructive reader-contributed unit conversion utility which has been submitted for addition to the official Revit SDK samples. We discussed the Revit unit handling in one of the very first posts to this blog. One main point discussed there is the fact that Revit internally uses a fixed set of internal database units which cannot be changed. For instance, all lengths are measured in feet. The post mentions the simple unit converter provided by the MidasLink... Read more →

Service-Oriented Architecture

A reader contributed the following introduction to Service-Oriented Architecture SOA. Even without having dealt with this paradigm previously, the recommendations made are all quickly recognisable as good practice, simply based on experience and striving for reliability and maintainability. This contribution is intended as a lead-in to an upcoming article and example code dealing with a specific Revit API issue: SOA provides an approach to writing code which has many benefits, not the least of which are promoting code reuse and... Read more →

Default Family Template Path

Question: Is any API exposed to read and write the default family template path? It is displayed under 'Default path for family template files' in the RAC 2010 options dialogue: Answer: Unfortunately, there is currently no way to set the path in the options dialog at runtime through the Revit API. You can read it from the Revit.ini file, though. It is stored under the FamilyTemplatePath key in the [Directories] section. Read more →

Free gbXML Webcast

We already mentioned the Green Building XML Schema or gbXML and how to export certain family instances to it. The gbXML Advisory Board is hosting a free webcast titled 'Using Green Building XML (gbXML) for Sustainable Building Design' on Wednesday, August 12, 2009 at 10:00 to 11:00 am PST. Presented by members of the gbXML Advisory Board, this webcast will demonstrate how tools for Building Information Modelling (BIM) can integrate with analysis software, using the interoperability of gbXML to help... Read more →

Online Revit Help

Help for the three Revit products is now available on the web, viewable in the browser. Links to the online help are provided on the documentation pages for each of the product centres: Here are the links to the product centres for the three flavours of the product: Revit Architecture Revit MEP Revit Structure These are the direct links to the help information for each of the three flavours: Revit Architecture Help Revit MEP Help Revit Structure Help The benefits... Read more →