The Building Coder

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 →

RVT and RFA Thumbnail Image

Here is a question that reappears pretty regularly. Question: How can I obtain the preview bitmap image or thumbnail from a Revit project or family file using the Revit API? This is an example of the kind of image I am interested in: Answer: The topic of getting your Revit thumbnails was already been discussed by Guy Robinson in Bolt out of the Red, but for completeness sake I will partially reiterate it here as well, since the query keep... Read more →

Selection Questions

A whole bunch of questions on selection of elements and points came in during the last day or two. Here are a few of them: How can I force the user to select an element when my external command begins? Answer... How can I invoke an existing Revit command when my external command begins? Answer... In the discussion of the Revit window handle and modeless dialogues you list selected elements in a modeless dialogue box. Could the reverse operation be... Read more →

Getting the Journal File Path

Here is an edited excerpt of an interesting and useful dialogue between Greg Wesner and Harry Mattison, both of Autodesk: I am building an application that needs to access the journal file when Revit saves a document. The path to the journal file can be found at Application.RecordingJournalFilename. But you only have access to this Application object when a command is executed and you get passed an ExternalCommandData reference in your command method. If you just want to create an... Read more →

Revit Install Path and Product GUIDs

Things were a bit hectic with many cases toward the end of last week, so less posts. By chance and luck, I was able to spontaneously join a ski tour on Sunday. The danger of avalanches is currently pretty high in most of Switzerland, and the weather was bad with lots of snow as well, so we evaded those problems by going way down south into Ticino and climbing Motto Crostel, 2302 m, from Faido and Tengia at 1099 m.... Read more →

Bolt out of the Red

Here is a short note to point out that Guy Robinson has posted some interesting Revit API solutions on his blog Bolt out of the Red. One that I found especially useful is on how to get a bitmap or thumbnail from a Revit project or family. Now he started a series on saving user specific configuration data for Revit commands using standard .NET functionality from the System.Configuration namespace, which has a number of pitfalls and requires some understanding of... Read more →

Revit Window Handle and Modeless Dialogues

Even though we cannot make use of the Revit API unless we are inside a Revit external command context, which is a modal state, there is still a lot of very useful functionality that can be provided with the help of modeless dialogue boxes. Modeless dialogues require knowledge of the Revit main window handle. As an example of a modeless dialogue, we will implement a form which is displayed in parallel with the Revit user interaction for selecting elements on... Read more →

AutoHotKey

Automate beyond the API ... Some parts of the Revit functionality are not yet accessible through the API, even though are repetitive tasks that are trivial to perform manually and a lot of work could be saved by automating them. One tool that many have found useful for this task and have published a number of working solutions for is AutoHotKey. Here is an AUGI discussion presenting a number of them, such as how to: Define F2 to open the... Read more →

Barcelona Questions

Thanks to Alex Vila Ortega of Autodesk Spain, I spent the last couple of days here in Barcelona giving a training class on the Revit API, with lots of professional and enthusiastic participants. Here are some of the questions that we explored. Question: How can I retrieve all the windows hosted by a specific given wall? Answer: Well, one possibility is to make use of the relationship inverter that we already discussed. This will provide a global dictionary mapping each... Read more →

Driving Revit from Outside

We are winding up here at Autodesk University, with a final panel session to meet the AEC API experts yesterday afternoon, and one on advanced use of the Revit API this morning. One topic that keeps cropping up in infinite variations and was mentioned several times in my sessions here at AU is how to drive Revit reliably from an application. The Revit API assumes that all interaction with the API functionality happens from within an external command. In general,... Read more →