The Building Coder

Build Your Own Document Changed Event

P.S. (pre scriptum) As Arnošt Löbel very kindly pointed out, I gave this post a rather misleading title. This post does not discuss the Revit API DocumentChanged event, which reacts when elements are modified. 'Build your own Document Activated event' would actually more closely advertise my intentions, at least to those of you who already familiar with the DocumentChanged event. Read on to see what it does discuss :-) Welcome to this extra day of the year, the bisestile invented... Read more →

Family Instance Room Phase

We already looked at some examples of confusion due to the interaction of phases with the room property on family instances. Here is a new aspect of this encountered and solved by Patrick Rosendahl of SOLAR-COMPUTER GmbH, who kindly explains the issue and its resolution like this: Problem: I am having a problem with the FamilyInstance Room property. I looked at the discussion of issues with the Room property and its phase dependency but have not been able to solve... Read more →

Hosting a Light Fitting on a Reference Plane

It is sometimes a challenge to determine which of the numerous overloads of the NewFamilyInstance method to use to achieve a desired effect. Here is a question on using it to host a light fitting by Simon Jones, with an initial answer by Saikat Bhattacharya, followed by lots more research by Simon to nail down the right solution that really works. Question: How can I host a light fitting onto a reference plane? I tried several different ways without any... Read more →

BIM versus Free Geometry and Product Training

Before even thinking about developing an add-in for Revit, i.e. before making any use of the Revit API, you first need to ensure that you have a good understanding of the Revit product and its philosophy. This is especially important for developers with experience with other CAD products, especially AutoCAD. Programming for a Parametric BIM versus Freely Defined Geometry In AutoCAD, as a developer, you have complete freedom to mess around with the database and its elements in any way... Read more →

Remove Imported JPG and BMP Images

Here is a query which helps understand how imported files are handled by Revit and how they can be removed from the model. Question: I want to remove imported images like JPG and BMP files from my Revit model. I tried to use a filtered element collector, apply its WhereElementIsNotElementType filter, select all elements whose name ends in ".jpg", and then delete them in a separate loop, but that does not seem to do it. Some other similar attempts also... Read more →

AEC DevCamp Coming Up Again

Happy Valentine's Day! Here is our Valentine's Day present for you, an invitation to our bi-annual AEC DevCamp: Are you interested in customizing, extending or integrating with Revit, Civil 3D, Navisworks, the Autodesk BIM 360 vision, Vault Collaboration AEC, Revit Server, new web services and mobile technologies, and more? If so, then the Autodesk AEC DevCamp is for you! When: June 6-7, with a DevLab on June 8 Where: Boston, Massachusetts – near Autodesk's AEC Division headquarters Cost: early bird... Read more →

Access Wire Sizes

Here is an interesting question that came up regarding the access to wire sizes. Using a filtered element collector to retrieve a TemperatureRatingType instance and attempting to read its wire sizes produces a problem that is in fact documented in the Revit API help file RevitAPI.chm, but the workaround is still worth pointing out. Question: I'm trying to access the wire size settings in a Revit model without success. The following code throws an exception saying "Object reference not set... Read more →

Add Reference Points and Markers Read from CSV File

For your convenience and my own future reference, here is a summary of a recent conversation with Dermott Mcmeel and a pointer to his video of the resulting add-in in action. Question: I'm using this wicked tutorial as a basis for a plug-in that will read info out of a CSV file. However, it's a few years old and from what I gather some of the definitions have been redefined our outdated. I've done the 'First Revit API plug-in tutorial'... Read more →

Revit Webcam 2012

I recently discussed the elimination of warnings about use of deprecated API methods from The Building Coder samples. In a similar vein, and for similar reasons, I also decided to migrate to Revit 2012 and clean up the RevitWebcam sample that I implemented to demonstrate the use of the Idling event when it was first introduced in the Revit 2011 API. Please note that this sample is intentionally not related to any BIM specific workflow. A webcam just provides an... Read more →

Element in View Crop Box Predicate

We had a look at one aspect of the interaction between element geometry and the view crop box last week when noting that section view geometry is not cropped. Here is another aspect: a useful little predicate function developer by Frode Tørresdal of Norconsult Informasjonssystemer AS to determine whether an element is contained in the crop box of a view. Question: Using the API I'm trying to determine if a detail item element is inside or outside the cropbox of... Read more →

Level Generator ADN Plugin of the Month

Another ADN Plugin of the Month for Revit has been published on Autodesk Labs: the February ADN Plugin of the Month is the Level Generator by my Chinese colleague Joe Ye. It generates multiple adjacent levels with one single command. Inside Revit, go to Add-ins > External Tools > Level Generator to start the command. The Level Generator dialogue appears: Existing levels are listed in the table with their Index and Elevation in gray colour and are not editable. To... Read more →

Section View Geometry Not Cropped

Here is a nice little chat with some interesting resulting hints that I had with an Australian programmer Bo that clarify the retrieval of geometry from a section view. The main point is that the cutting plane of the section view does affect the retrieved geometry, whereas the view's bounding box does not. Here is the path we took to clarify this in all its gory detail: Question: I am working on a structural concrete design application and would like... Read more →