The Building Coder

Formatting unit strings

What methods can I use to create a properly formatted unit string according to the project units? If the value you are formatting resides in a Revit parameter, the answer is simple and a complete solution immediately provided by the Revit API. On one hand, the Parameter class provides the following public methods to read and write its parameter value: AsDouble: Provides access to the double precision number within the parameter. AsElementId: Provides access to the element id stored within... Read more →

Running AutoCAD inside Revit

The preceding post on RealDWG and object enablers discussed one potential method for making use of AcDb functionality to read and write AutoCAD DWG files inside of Revit. Assuming that you have a license for a full version of AutoCAD in addition to your Revit one, there is another easy method to achieve this which has been implemented and tested. It is possible to run AutoCAD as a full-blown process in the background inside Revit. This functionality is new in... Read more →

RealDWG and Object Enablers

Revit uses the RealDWG toolkit to implement the DWG file export and import functionality. A frequent question is whether there is any way to hook into this functionality, and how this relates to custom objects and DBX object enablers, like for instance: Is there a way to load a DBX application into Revit as a RealDWG extension? It would be handy to be able to reuse the functionality of some custom ObjectDBX classes. First of all, let us clarify some... Read more →

Defining a New Parameter

Here are some frequent questions regarding the creation of new parameters: I want to store a new parameter in a Revit document. Is there a way to do this without binding it to a specific category? Is it always necessary to create a shared parameter file in order to store new parameters? Do I need such a shared parameter file for each Revit file in which I want to store this new parameter? How can I store one single instance... Read more →

Exploring Element Parameters

Most non-geometrical element data in Revit is stored in element parameters, so this is obviously an important topic, and one that we have not explored much yet. We did touch on it when discussing adding a shared parameter to a DWG file, and now we will recapitulate some basics and discuss the built-in parameter checker, which is a useful tool for exploring element parameters. First some brief basic facts of life on parameters. They are discussed in more detail by... Read more →

Another Revit API Blog

My friend Monika just pointed out Matt Mason's blog to me, mainly due to his nice praise for The Building Coder. Thank you, Matt! And thanks to Monika for pointing it out. Matt covers a variety of CAD application development topics, with the main focus on Revit, judging from the current tags: AutoCAD 1 Autodesk 2 DotNet 2 DWF 2 Events 4 Google Earth 1 Intent 1 Inventor 4 Revit 32 Vault 1 He is Director of Software Development at... Read more →

Visual Studio 2008

Can I use Visual Studio 2008 to develop Revit API applications for Revit 2009? The Revit API is .NET based, which insulates you from certain low-level details and enhances portability and interoperability compared to a more directly linked API such as C++. Kean Walmsley just published a little note on obtaining and using Visual Studio 2008 in his blog on the AutoCAD.NET API. The notes about developing .NET applications for AutoCAD apply to Revit development as well. Officially, as stated... Read more →

Wall Elevation Profile

In this post, we explore how to determine the wall elevation boundary polygons, similarly to the floor boundary polygon algorithm. This functionality is frequently requested, last but not least in a comment by Art. The approach is similar to the one for the floor boundary polygons, with some small additional twists. To determine the floor boundary, we simply searched for one of its two horizontal faces and queried it for its edge loops. For a wall, it is slightly more... Read more →

Wall Compound Layers

We have examined floor and slab geometry in some detail now, and would like to have a look at walls as well. One important aspect of walls is their internal layering, defined by the compound layer structure. In this post, we examine the layer geometry, i.e. how to determine the exact location of the different layers within the wall structure. Many thanks to Harry Mattison for providing lots of support developing this code and explaining both the API and the... Read more →

Editing a floor profile

A question that recently came up was how to edit an existing floor profile. This also leads to the question of whether one can access the existing sketch lines through the API and modify them. In the user interface, one can enter the Floor Edit mode and modify the sketch lines of a floor. In the API, this is not possible. However, it is possible to simply recreate the floor with a new curve array. The next question that pops... Read more →

Adding a Shared Parameter to a DWG File

I was recently asked whether it is possible to attach a shared parameter to a DWG drawing file imported into a Revit model. The exploration of this issue was interesting enough for me to like to share it. First of all, if you are interested in attaching a shared parameter to Revit elements, there are some pretty clear examples available demonstrating how to achieve this. One is the FireRating sample in the Revit SDK, the other is the Revit API... Read more →

Loading The Building Coder Samples

As I write these blog entries, I continuously add new commands to The Building Coder sample project. While doing so, I wish keep my list of external commands up to date with a minimum of effort. I have several important requirements: Maintain one single file listing the command information. Automatically create an entry point in Revit for each command. Reuse the same file in all flavours of Revit, with no additional effort. Integrate the command data with other ADN samples... Read more →

Creating a new Type

This post is due to Joe Ye in our Beijing office. Many thanks, Joe! While proof reading my handouts for the Revit API tips and tricks session at AU, DE205-3 Enhancing Your Revit Add-In, Joe pointed out that creating a new type or family symbol is a hot topic often asked by developers. It is not obvious from the Revit API help documentation or samples how to achieve this. It is simple to solve, though: one can use the Duplicate()... Read more →

Slab Side Faces

In the preceding post, we discussed the creation of model lines to graphically display certain polygons in space for debugging purposes. The polygons we display are slab boundaries calculated by iterating over all the horizontal faces of the slab and choosing the lowest one to extract its edge loops from, which represent the polygonal slab boundary loops. In this post, we demonstrate another use of this model line creator. We expand it to calculate and display the normal vectors of... Read more →

Model Line Creation

In the previous post, we determined the slab boundary polygons and displayed the resulting polygon data graphically for debugging and better understanding by creating model line segments for them in the Revit database. We did not go into any detail about the code to create those model lines, which is an interesting little topic all in itself. It is packaged in a utility class named Creator, since it encapsulates a small subset of the functionality provided by the Autodesk.Revit.Creation namespace.... Read more →