The Building Coder

Fire Rating Zone Intersection

Let's tackle a 2D fire rating zone intersection task. Actually, it was originally raised a 3D intersection task. Reducing it to 2D makes it much more tractable – 3D solid extrusion creation and intersection task – 2D area intersection task – Jack's sample and description – Soffit subdivision sample code – Cleanup and GitHub repository... Read more →

Efficient and Elegant Code

I remain busy, mainly in the Revit API discussion forum. Here are three recent samples dealing with pretty generic questions – Efficiency and elegance in simple code – Pushing wall type to doors... Read more →

Tailor Your BIM with F#, Forge, IFC and Takeoffs

I have a whole bunch of exciting overdue topics lined up. Let's start with these – Tailor Your BIM sums room areas with F# – Control view for design option elements with F# – Copy legend view and component from background file – Forge RVT to IFC translation defaults to 2x3 – Latitude and longitude in Revit IFC export – Takeoff creation requires branch duct... Read more →

Protecting a Family from Tampering

The Forge accelerator in Rome is winding down with the demonstrations of what was achieved being recorded as I write. An interesting conversation I had at the celebratory dinner last night gave me an idea for a solution to a longstanding question on family tampering protection – Roma accelerator group photo – Protecting a family from tampering – Implementing a canonical key for geometrical objects... Read more →

Floor Area Above Room and Mysterious Hide

Today, we focus on two pure programming questions from the Revit API discussion forum – Area of an exterior floor above a room – Mysterious element hiding activity... Read more →

Rebar, Wall Centreline, Core and Grid Dimensioning

My colleague Zhong John Wu just solved a Revit API discussion forum issue on how to create dimension line for rebar. I took this as a prompt to clean out a bunch of other dimensioning related issues lurking in my infinite and growing to-do list – Create dimension line for rebar – Newly created dimensioning not displayed – Dimension leader remains visible after removal – Dimension wall centreline, centre and faces of core – Grid references for dimensioning... Read more →

Support DLL, Zero Doc State and Forge Accelerators

If you are interested in Forge programming, don't miss the upcoming deadline for proposals for the Boston Forge accelerator! Looking at the Revit API, I migrated my sample demonstrating how to enable ribbon items in zero document state to Revit 2019. Let's look at that, and another recurring topic, on loading add-in support DLLs – Migrating the ZeroDocPanel to Revit 2019 – Loading add-in support DLLs – Rome and Boston Forge accelerators... Read more →

Reference Intersector and Deleting Reference Planes

We already looked at deleting unnamed non-hosting reference planes back in 2012 and 2014. Some things have changed since then, and the old code requires fixing and updating. Other interesting topics also want to be mentioned – Embodyment workshop – Bös Fulen mountain hike – Using ReferenceIntersector to place lighting fixture on ceiling face – Reformat stable representation string for dimensioning – Deleting unnamed non-hosting reference planes updated... Read more →

Forge Tutorials and Filtering for a Parameter Value

Today, let's revisit the topic of filtering for a parameter value, and mention the updated Forge tutorials – Learning Forge tutorials – Filtering for a specific parameter value – Filtered element collector optimisation... Read more →

FilterRule Use and Retrieving Exterior Walls

Today, we revisit the interesting and generic question on retrieving all exterior walls. That may be easy in a perfect and complete model. However, it raises some challenges in an incomplete BIM – Retrieving all exterior walls – Several possible approaches – Using a computational geometry approach – Manually adding the huge surrounding room – Encapsulate transactions and roll back instead of deleting – Determining model extents via wall bounding box – Implementing the huge surrounding room approach – Retrieving family instances satisfying a filter rule... Read more →

Parameters, Walls and Driving Revit via WCF Service

Exciting news from Russia and some mundane updates on other repetitive topics – Driving Revit from a modeless context via a WCF service – Room walls' directions – Retrieving all exterior walls – Getting and setting a shared parameter value... Read more →

Revit 2018.3, SetValueString and External Events

I installed the latest Revit update, and want to highlight two of the numerous interesting ongoing Revit API forum discussions – Revit 2018.3 update – Avoid SetValueString – Passing Data via ExternalEvent.Raise... Read more →

Standalone BasicFileInfo and ExtractPartAtom

A discussion with Håvard Dagsvik on the use of TransmissionData, standalone access to the BasicFileInfo without the need for a valid Revit API context, and a Revit-independent method replacing Family ExtractPartAtom – No document required for TransmissionData access – TransmissionData requires a valid Revit API context – Standalone GetFamilyXmlData method replacing ExtractPartAtom – Windows explorer BasicFileInfo right click utility... Read more →

Using Intersection Filter with Linked File

We recently discussed filtering for intersecting elements. Here is a closely related issue with an additional twist – Determining elements intersecting mass in a linked file – Coding suggestions and transformations – Solution by applying transformations... Read more →

Connector, Neighbour, Conduit, Transition

Here are a couple of threads from the Revit API discussion forum related to MEP and connectors from the past few weeks that seem worth taking note of – Traversing an MEP system and retrieving connected elements – Reproducing the MEP electrical system browser hierarchy – Creating a conduit between two connectors – Dealing with the read-only transition diameter... Read more →

Switch View or Document by Showing Elements

A recent discussion on using the ShowElements method to toggle between documents and views brought up a few interesting points – Open and active an unsaved document – Zoom to selected elements – Toggle between documents and views... Read more →

Create 2D Arc and Filter for Intersecting Elements

Several questions on filtering for intersecting elements came up recently. It is pretty easy as long as a bounding box can be used. However, the bounding box is generally aligned with the cardinal X, Y and Z axes. If the containing volume of interest is not, too many elements may be selected – Family instances in a diagonal room – Conduits intersecting a junction box – Generate 2D arc from radius, start and end points... Read more →

Retrieving Newly Created Element Ids

An add-in will often need to retrieve the elements that it just created for further processing. Frequently, the Revit API method used to create them will return their element ids. Sometimes, that is not the case. Now this topic arose again in a couple of cases and brought some other aspects to mind – Using the element lister – Consecutive element ids – Retrieving recently added elements – AEC job openings in Munich and elsewhere... Read more →

DirectShape from BrepBuilder and Boolean

Here is an interesting code snippet illustrating the use of BRepBuilder and Boolean operations to generate a DirectShape. It might come in useful somewhere, even though this approach is non-optimal to address the task at hand, as explained below... Read more →

Create Swept Blend DirectShape in C++

Question: I am trying to create a swept blend geometry and assign it to a DirectShape element. The initial code threw an exception when calling the GeometryCreationUtilities CreateSweptBlendGeometry method. How can I fix this? Answer: The path parameters assume that they should be normalised or that the curve has a range of parameterisation from 0 to 1... Read more →

Project Identifier and Fuzzy Comparison

I bring up two recurring topics, fresh every time around – Project identifier – Fuzzy comparison versus exact arithmetic for curve intersection... Read more →

Automatic Wall Creation

Alexander Ignatovich shares an exceedingly elegant solution for automatic wall creation, illustrating a number of important concepts and implementing the following functionality very succinctly indeed – Retrieve all the cube family instances – Retrieve their height parameter value – Retrieve their solids making use of the .NET yield operator – Extract their horizontal outline contours using an ExtrusionAnalyzer – Create walls along each contour curve segment – Place a door family instance at the midpoint of each wall... Read more →

Curtain Wall Panel Geometry with Basic Wall Panel

A quick geometrical question on retrieving geometry from a basic wall being used as a panel in a curtain wall. I am struggling to retrieve the geometry data from a curtain wall that contains a Basic wall in one of the curtain wall panels. My example curtain wall has two panels. With one of the panels, a basic wall type is associated. I need to get the geometry data (i.e., the faces) for the entire curtain wall. When I reach the second panel in my code, the SymbolGeometry contains zero objects, so my code cannot retrieve any geometry for it... Read more →

Disjunct Planar Face Outer Loops

I am attending the Forge DevCon conference in Darmstadt, Germany, right now, and putting the final touches to my presentation on Rational BIM programming using Revit and Forge at the European Autodesk University on Wednesday. We discussed several different approaches to retrieve the outer loop of a planar face. Richard Thomas recently shared a possible solution to determine the outer-most EdgeLoop. He now posted a new approach: I found a more straightforward and likely reliable way of getting outer loops of planar faces. This method also allows for faces made up of disjointed parts... Read more →

Birthday Post on the XYZ Class

Today is The Building Coder's ninth birthday. We'll celebrate by discussing the pretty fundamental issue of XYZ points versus vectors, and how to distinguish different points – XYZ point versus vector – How to distinguish XYZ points... Read more →

Picked Instance Face Geometry in LCS Versus WCS

Depending on circumstances, interactively picked family instance geometry may be returned in the global Revit world coordinate system WCS, or in the family instance definition local coordinate system LCS. A family instance may have its own non-empty solid, or use the symbol geometry. The symbol geometry requires keeping track of the instance transform to map it to the actual instance project location – Question on Incorrect Face Normal – Working Plane has no Effect – Non-Picked Face Normals are Correct – Solution – Detecting When to Use LCS versus WCS – Retrieval of Picked Geometry Face from Instance is Untransformed... Read more →

Finding an Exit Path and ElementId Parameter Values

As usual, lots of exciting discussions are being conducted in the Revit API discussion forum. I'll just highlight two of them going on right now – Finding a path through the BIM – Finding all possible ElementId values for specific Parameter... Read more →

Determining Dimension Segment Endoints

A rather hard struggle led to a rather simple solution for determining the start and end points of dimension segments. In summary, the solution looks like this – A Dimension element is either single- or multi-segment; these two cases need to be handled separately – In case of a single segment, the dimension element itself has a line, an origin and a value; the line is indeed the dimension line. However, it may be unbounded... Read more →

Sensors, BIM, AI, RevitLookup, Fuzzy Comparison

We continue patrolling the well-trodden paths of BIM, AI, Revit precision and RevitLookup – Connected BIM – Intuitive AI – Fuzzy Comparison – RevitLookup 2018.0.0.1... Read more →

Retrieving Elements Visible in View

Minho re-opened the Revit API discussion forum thread on getting the ElementId of all visible entities in a viewport, providing a good opportunity to mention Colin Stark's answer to the StackOverflow thread on determining whether a FamilyInstance is visible in a View. Question: I am looking for code to get the ElementIds of all entities inside a viewport. A viewport is a region of a big view plan... Read more →

ForgeFader, Lookup Builds, Purge & Room Instances

Blogging despite having already exceeded my work quota for the week, but there is so much to share – ForgeFader user interface – RevitLookup builds – Purging types, families and materials – Retrieving all family instances in a room... Read more →

WTA Mech and TTT for Provision for Voids

Today is the last day of the Forge accelerator, and I am still working on the ForgeFader project. The topics today are mainly related to Revit, though – Google prettifier on GitHub – WTA mechanical family placement add-in – Provision for void – What is a provision for void? – Creating a provision for void... Read more →

Three.js Raytracing in the Forge Viewer

Yesterday, I showed how you can add custom geometry to the Forge viewer for debugging or other purposes and to control graphically what is going on. Today, I address the ray tracing required to determine the number of walls between the user selected signal source point and the other target points spread out across the picked floor slab. Please note the important information in the final section: the viewer implements built-in raycast functionality that obviates the need for this – Connecting Visual Studio Code to the Chrome debugger – Creating a three.js mesh from Forge viewer fragments – Use built-in viewer raycast instead... Read more →

RvtFader, AVF, Ray Tracing and Signal Attenuation

I implemented a neat new little sample add-in, RvtFader, that calculates and displays signal attenuation caused by distance and obstacles, specifically walls. It uses two very interesting pieces of Revit API functionality – AVF, the Analysis Visualisation Framework, for displaying graphical data in a transient manner directly in the BIM – The ReferenceIntersector ray tracing functionality to detect walls and other obstacles between two points. In the course of implementing the AVF part of things, I also resuscitated my trusty old RevitWebcam add-in – RevitWebcam – RvtFader – Task – Implementation – Further Reading... Read more →

Family Bounding Box and AEC Hackathon Munich

I briefly mentioned the AEC Hackathon in Munich yesterday. Here is some more information on that, highlighting the exciting speaker line-up and target topics, plus a solution for determining the bounding box of an entire family – AEC Hackathon Munich Topics and Speakers – Family bounding box – Continuous integration for RevitLookup? Read more →

UIView Windows Coordinate Ray Casting Tooltip

I revisited the custom tooltip implementation that I prepared to demonstrate the Revit 2013 API features including the View API and its UIView class. It class still provides the only possibility to convert back and forth between Revit model coordinates and Windows device screen points. That functionality can be combined with the ReferenceIntersector to shoot a ray through the model to determine what Revit database element is located under the current cursor position and display a custom tooltip presenting information about it or anything else you please... Read more →

Schedule Parameters and Shared Parameter GUID

Lots of information on, from and about schedule parameters, and a new elegant solution to a long-standing challenge – Direct access to shared parameter GUID – Getting parameter information from a schedule... Read more →

Distances, Switches, Kiss-ing and a Dino

I continued my activity in the Revit API discussion forum and had lots of interesting discussions there. One recent thread caused me to bring up a favourite topic of mine, on keeping things simple. I'll also mention two other less recent recurring questions – Distance between two points in a specific direction – Revit command-line switches – Keeping things simple with the Revit API – Dino pondering lengthening days... Read more →

Determining Views Showing an Element

The topic of how to determine all views in which a given element is visible has been discussed several times on the past, and a couple of viable solutions have been suggested. However, for large projects, performance becomes an issue. This question was raised again by Abba Lustgarten and Erik Eriksson in the Revit API discussion forum thread on finding views in which an element is visible (by geometry or actual visibility), with Erik sharing a View extension method IntersectsBoundingBox that helps alleviate the performance impact... Read more →

Warning Swallower, Roomedit3d Viewer Extension

I continue my work on the roomedit3dv3 sample connecting the desktop with the cloud by enabling a real-time round-trip modification of the BIM via the Forge viewer, mention a neat solution enabling a Revit add-in to swallowing warning messages, and point out the Forge webinar session on the Forge Viewer later today – Warning swallower – Roomedit3dv3 transform viewer extension – Forge webinar series... Read more →

HoloLens Escape Path Waypoint JSON Exporter

Last week, I worked with Kean Walmsley on his entry for the first global Autodesk Hackathon: a HoloLens-based tool for navigating low visibility environments, resulting in the new HoloGuide Autodesk Hackathon project. My modest contribution is the ExportWaypointsJson Revit add-in, an external application implementing the main command, exporting the waypoints, and a subsidiary option settings command, displaying a form, validating input and storing the user preferences. The main command simply prompts the user to pick a model line in the Revit project, traverses it, determines waypoints at predefined intervals and exports them to JSON for consumption by the HoloGuide visualisation... Read more →

Online Revit API Docs and Convex Hull

Today I happily present a brilliant piece of Revit API news on the documentation side of things, and another handy utility method for your Revit API programming toolbox – Online Revit API Documentation – 2D Convex Hull Algorithm in C# using XYZ points... Read more →

MEP System Structure in Hierarchical JSON Graph

Yesterday, I presented the new TraverseAllSystems add-in to traverse all MEP system graphs and export their connected hierarchical structure to JSON and XML that I am helping the USC team with here at the San Francisco cloud accelerator. I continued with that today, and also integrated a minor enhancement to RevitLookup – TraverseAllSystems updates – Shared parameter creation – Options – Bottom-up JSON structure – Top-down JSON structure – TraversalTree JSON output generator – TreeNode JSON output generator – Download and to do – RevitLookup updates... Read more →

Highlighting Revit Rooms in the Forge Viewer

I am leaving Athens today. The Athens Forge meetup and web server workshop at The Cube went well. Now it is full steam ahead towards the Forge DevCon in San Francisco week after next. Not to forget the 3D Web Fest on June 15, in parallel with Forge DevCon, showcasing the best of the 3D web as live performance art with a catered reception in a film festival atmosphere... Read more →

Filtering for View Specific Elements

While preparing for the Forge DevCon in SF and the Athens Forge meetup and web server workshop at The Cube Athens, I also happened to hear about the solution to the question raised by Chema in the Revit API discussion forum thread on deleting an area in a drafting view – I need to delete some elements (detail items) in a given area of my drafting view... Read more →

Reference Stable Representation Magic Voodoo

Let's end the week with a truly magnificent contribution and research result provided by Scott Wilson in the Revit API discussion forum. Scott responded to Pat Hague's recent thread on converting local family instance coordinate of a selected edge to project coordinates, saying, Yeah the Stable Reference Strings can be used to get at areas of the Geometry API that aren't fully exposed – I love playing around with them. Sometimes I stumble upon something cool such as this solution for a situation in which the geometry returns no reference for a family instance... Read more →

More on Wall Opening Areas per Room

Håvard added some clarifications and background information on his sample code to determine wall opening areas per room: I have some questions on Håvard's initial approaches. Using a Boolean subtraction between transient solids from the actual wall and the family symbol sounds like the right track, but I don’t understand the need for the family instance, because the wall already provides the net geometry... Read more →

Determining Wall Opening Areas per Room

We continue the rather exhaustive exploration of calculating net and gross wall areas per room, and two other announcements, pointers to interesting sources of information – Why Autodesk has a Labs – Dal BIM in poi – Italian BIM – Determining wall opening areas per room – Håvard's SpatialElementGeometryCalculator enhancement – External command mainline – Test run... Read more →

Determining Wall Cut Area for a Specific Room

We looked at calculating gross and net wall areas last year, with a later enhancement to use IFCExportUtils to determine the door and window area, resulting in the two respective projects and GitHub repositories, SpatialElementGeometryCalculator and ExporterIfcUtilsWinArea. Several developers have been busy expanding on those to determine surface areas of subfaces, for instance for openings in walls spanning multiple rooms... Read more →

Location of Hooks in a Rebar Shape Family

Here is a slightly tricky structural rebar Revit API issue raised in the Revit API discussion forum thread on getting the location of hooks in a rebar shape family: When editing a Rebar Shape family I would like to find out what lines in the family the hooks are attached to. In other words I would like the id of the line the start hook is attached to and the coordinate of this hook... Read more →