The Building Coder

DevDays, Keynote Manager and REX Extensions

Let's highlight a few recent threads from the Revit API discussion forum. Before getting to those, a quick pointer to the DevDays Online recording from last week – DevDays online presentations on Revit API updates – External command with ribbon button sample – RevitAddinKeyNoteSystem keynote manager – REX extensions versus Revit add-ins – Reloading Revit links from user selected folder – Converting all parameter values to metric... Read more →

Avoid Exorbitant Coordinates

Slabs created by an add-in are displayed perfectly in Revit 2015. In Revit 2016, they are not. What can be the problem? These slabs are located at an exorbitant distance from the origin. Relocating them closer to the origin resolves the problem... Read more →

AU Recording, Books, Education and Units

I completed the presentation and recording of my presentation yesterday on Rational BIM programming using Revit and Forge at Autodesk University in Darmstadt, Germany – Rational BIM Programming recording – Pleasant walks in the Odenwald – Some of my favourite recent books – Where to continue after finishing school – New AlphaGo Zero is completely self-taught – TotalPressureLoss units... Read more →

Unit Abbreviations

Håvard Dagsvik of Symetri implemented code to automatically generate a dictionary mapping the Revit DisplayUnitType to corresponding UnitSymbolType display strings. The developer guide describes these classes like this – UnitType – type of physical quantity to be measured, for example length or force (UT_Length or UT_Force) – DisplayUnitType – units and display format used to format numbers as strings or convert units (i.e. DUT_METERS) – UnitSymbolType – unit symbol displayed in the formatted string representation of a number to indicate the units of the value (i.e. UST_M)... Read more →

UnitUtils Converting Units for Unit Weight

Here comes a quick clarification of the units used for the UnitWeight built-in parameter PHY_MATERIAL_PARAM_UNIT_WEIGHT. One example usage is to calculate the total weight of rebars in a project... Read more →

Type Catalogues

Let's veer away from the Revit API for a moment and take a look at family type catalogues, since questions on those pop up regularly in connection with programming as well: Programmatic type catalogue creation Tweaking type catalogue behaviour Type catalogue parameters Type catalogue units Programmatic Type Catalogue Creation Question: Is there any API support (function) to create type catalogues? Answer: As far as I know, there are two ways to create type catalogues, and both are programmatically accessible: Create... Read more →

Getting Started Creating Families and RFA Files

Here are some more pointers for getting started generating family definitions and RFA files programmatically: Family types and parameters Imperial internal Revit database length units Programmatically generating Revit family RFA files I am writing this from the Greek island of Euboea, on which I already visited Limni or Λιμνι on the north end a couple of years ago. This time, I am heading towards its east and south end instead, on my way to the second I love 3D –... Read more →

Berlin Hackathon Results, 3D Viewer and Web News

We completed the Berlin hackathon last weekend, and many other noteworthy and exciting things are going on, concerning the Revit API, the 3D web viewers, web services and more: Berlin hackathon projects and winners Avoid unnecessary unit conversion 3D viewer news AutoCAD as a web service Collada STL ADVA export settings RvtVa3c update Berlin Hackathon Projects and Winners The Berlin hackathon completed and the winners were announced last weekend. I took notes of four teams' project presentations: US4, us four... Read more →

New Text Note and Text Width Calculation

How can I determine the exact width of a Revit text note? This is the topic of the Revit API discussion thread on textnote width calculate minimum. We worked through a whole series of implementation attempts, mostly suggested by Scott Wilson, who also finally suggested the one that currently seems to be optimal and near perfect: Question: When creating a new TextNote I'm given the option to give the TextNote a LineWidth Property. I understand this is the 1:1 scale... Read more →

Localised Unit Abbreviations

I recently discussed how to generate unit abbreviations, both using a hard coded list and automatically generating them from the UnitSymbolType enumeration values. I implemented the CmdDutAbbreviation command in The Building Coder samples to test these abbreviations, and also enhanced it to display the Display Unit Type to Unit Types mapping that we added in the meantime. Victor Chekalin, or Виктор Чекалин, reacted to this analysis and adds: Thank you for your investigation. But... There is a big 'but' :-)... Read more →

Determining Host Document Location of a Linked Element

It is getting rather cold and wet and dreary outside now, so I spent some time answering the following excellently documented developer query on relating the coordinates of a linked file with its host. Just as I was about to publish it, Kon raised the very same issue in a comment on the recent discussion on accessing individual elements in linked projects: "When I try to relate the 'internal' XYZ LocationPoint of the linked document to the main model, they... Read more →

Mapping Display Unit Type to Unit Types

Yesterday, we looked at unit abbreviations and some other aspects of the new Revit 2014 Unit API. I mentioned that one might be able to use the FormatUtils.Format or UnitFormatUtils.Format methods to generate a string representation of a given numeric value, extract a unit abbreviation from it, and that I was not looking further at that option, lacking a UnitType to feed it with, only having a DisplayUnitType to work with. That led me to wonder whether there might be... Read more →

Unit Abbreviations

Today, we look at determining the units for a given parameter, and specifically providing a suitable unit abbreviation for it. The Revit 2014 API introduced a new Unit API with a large number of enhancements to complete and simplify unit handling issues, and I have not yet explored all of them in depth. Here is the overview of it from What's New in the Revit 2014 API: Units API The API for Units in Revit has been expanded and changed.... Read more →

Curve Length, Idling, Units and RevitPythonShell

Here are a couple of recent interesting questions that came up: Curve Length versus ApproximateLength Potential SetRaiseWithoutDelay workaround Unit handling improvements Self-contained RevitPythonShell deployment Curve Length versus ApproximateLength Question: What is the difference between the Curve Length and ApproximateLength properties, please? I am using them to obtain an arc wall length. As far as I can tell, the result is exactly the same, so which one should I normally use? Answer: All Revit geometry curves are parameterised. A curve is... Read more →

Migrating The Building Coder Samples to Revit 2014

I started migrating The Building Coder samples to Revit 2014. Funnily enough, on the exact same date as last year for the previous version. The changes are very small this time around. Furthermore, I am well prepared, since I recently intentionally eliminated all compiler warnings and deprecated calls compiling the code for Revit 2013. First, however, a picture or three from my ski tour last weekend over Il Chapütschin (3386 m) and La Sella (3584 m) in the Swiss Engadin.... Read more →

Units and RevitLookup

Here is a typical question from a Revit API newbie that prompts me to reiterate some important basic beginner information on units and the RevitLookup tool for exploring the Revit database: Question: How can I retrieve the length and mass units from a Revit document? Answer: The internal Revit database length unit is always imperial feet. That cannot be changed, so there is you answer for that. Similarly, the internal database unit for weight is kg, as far as I... Read more →

Revit 2013 Unit Conversion Utility

Here is a Revit 2013 update of the Revit 2011 unit conversion utility, originally posted and described for Revit 2010, by Harry Mattison. In his own words: I was looking at the great unit conversion utility and created a new version upgraded to Revit 2013 that I thought you readers might enjoy. I ran into one issue that required a code enhancement to catch an exception thrown by many parameters, such as HVAC_Temperature, HVAC_Slope, etc. The rest of the code... Read more →

Point Cloud Unit Conversion

Happy New Year of the Dragon! Top: Happy New Year! Bottom: Lucky Peace! The Chinese dragon is the symbol of emperor and power. Thanks to Joe Ye and nipic.com for the image and translation! Besides programming Revit and climbing mountains, I also like climbing trees: Returning to the Revit API, the topic of units is a recurring theme, and here it is again rearing its beautiful head in the context of point cloud data access: Question: I am working on... Read more →

Unit Conversion and Display String Formatting

AU went very well for me, and I think this was the one I liked most of all so far, to my own surprise. Now I am already at the next conference in Moscow, from where I continue to Tel Aviv tomorrow. December is always my monster travelling month, and I never get to prepare for Christmas or enjoy the dark and cosy celebration of Advent. But I really did have fun and enjoy AU in Las Vegas. Sunday morning... Read more →

Internal Imperial Units

To start off this week, here is a pretty useless question that still seems to be of great interest to many people: Question: Odd question perhaps, but why does Revit internally work in imperial units? Answer: I do not find your question odd at all; many others wonder that as well, I am sure. Briefly, I would hazard that the answer is simply that this is a religious question, or a question of taste, or historically evolved. Does that satisfy... Read more →

Unit Conversion and New Blogs

Quite a while back, I published a unit conversion utility for Revit 2010. Let's take a fresh look at that, and also at a couple of new Revit blogs. We discussed a couple of other issues related to units since then, such as the unit suffix and ProjectUnit SDK sample and a look at voltage units. The latter also includes an overview of some other unit related posts. Anyway, Rod Howarth picked up on the unit converter utility and ported... Read more →

View Location on Sheet

I returned from a beautiful little mountain hike to the lake, pass and mountain of Piz Lunghin. One very special aspect of this place is that it is Europe's one and only triple watershed, with rivers flowing all the way to the North Sea, Black Sea and Mediterranean. Another special aspect of my hike was spending the night outside on the mountain, with a wonderful clear sky and the almost full moon in sub-zero temperatures (Celsius). Returning once again to... Read more →

Ribbon Icon Resolution

We are still on the Pantagruel, currently sailing from Norway to the west coast of Sweden. Here is a view from Preikestolen down into Lysefjord, where we went for a hike before leaving the Stavanger area: Here are some of us on deck the first day: That was before getting out onto the open sea and into higher winds, causing us to feel a lot less chirpy: The weather has been pleasant all the time, but the wind is very... Read more →

Slope is Slope, Not Radians

I am still in Thailand, flying home tonight. Still, I had time to go through some email today, and picked up lots of interesting tidbits. Let me start with this one: Question: When I use the sample code from the Revit API help file RevitAPI.chm to create a NewFootPrintRoof, the slope is set to 0.5 radians. This results in a slope of 26.57 degrees for the newly created roof. This value is incorrect, however, since 0.5 radian equals about 28.65... Read more →

Voltage Units

The last day before DevCamp! I am happy to note that the articles on grabbing a webcam image and displaying it on a Revit element face were so popular ... I will be demonstrating that and other samples using the Idling event and modeless dialogues at DevCamp. Meanwhile, here is an interesting little item that my colleagues Jorgen Dahl and Martin Schmid (who by the way published a book on AutoCAD MEP 2010) dug up, another nugget of information on... Read more →

Parameter Filter Units

The Western European DevDays conference tour has begun, and I will be presenting and travelling all week, leaving very little time to spend blogging or responding to comments. I visited relatives in London the preceding weekend, and took some time to write and post this before the real crunch began. Several previous posts deal with various aspects of unit handling in the Revit API: Units. Formatting unit strings. Unit types and format options. Unit conversion. Unit Suffix and the ProjectUnit... Read more →

DUT versus UST

After a wonderful weekend in the Swiss alps climbing the Diechterhorn, here is a follow-up explanation by Jeremy Sawicki of Autodesk on the difference between DisplayUnitType and UnitSymbolType in continuation of our last discussion on the unit suffix. Question: What is the exact difference between DisplayUnitType and UnitSymbolType, please? For instance, the default project unit settings on my system for a length are DUT_Millimetres and UST_None ... I wonder what exactly that means? Also, can you suggest a way to... Read more →

Unit Suffix and the ProjectUnit SDK Sample

We delved into various aspects of units in several previous posts: Basics on units. Formatting unit strings. Unit types and format options. Unit conversion. And still the topic is not exhausted. Here is a new point to consider: Question: Is there a way to retrieve the unit for a parameter? I can read a parameter's value and its Display Unit Type but not the unit's symbol, the display string suffix used to represent the unit in the user interface. For... Read more →

Display Strings and Enumerations

Question: I need to get the string value displayed in the Revit user interface for some parameters whose values only contain an integer value, such as: Wall Function: the API returns an integer value, whereas the UI displays "Exterior". Wrapping at Inserts: again, the API returns an integer value, whereas the UI displays "Both". Is there a general way to get a mapping between the integer values and the display strings for all such items in Revit? Answer: For a... 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 →

Scale a Curve

Now let us get back to really practical things again, after the practical notes on impractical things, and the more or less practical boot camp note. Question: I have a CurveArray object containing data defined in inches. Now I need to scale it to feet in order to feed it into a Revit API method to create an extrusion. How can I perform this scaling operation? I would obviously prefer not having to rebuild the entire CurveArray. How does one... Read more →

Think Big in Revit

A couple of cases dealing with issues concerning small dimensions in Revit were recently raised by Toste Wallmark of Tecton Limited and Henrik Bengtsson of Lindab: Minimal length required when calling NewLineBound. Minimal possible family component dimension. Minimum scaling factor for annotation family symbol. Minimal Length in NewLineBound Question: I have discovered that NewLineBound throws System.ArgumentException "Value does not fall within the expected range" when the values are close or very close. Is that an expected behaviour in this case?... Read more →

Inserting a Beam

This is the final Verona installment, discussing the last remaining topic raised in the Revit API training in Verona the week before last, on creating new beam types and inserting beam instances through the API. Similar to the exploration concerning columns, we explored the following topics: Retrieving all matching family elements in current document in order to check whether the family we are interested in is loaded. Exploring the results of using a FamilyFilter. Loading a new family, if not... Read more →

Inserting a Column

Here I continue the discussion of another of the topics that were raised in the Revit API training in Verona last week, on creating new column types and inserting column instances through the API. We explored the following topics: Retrieving all family elements in current document in order to check whether the family we are interested in is loaded. Exploring the results of using a FamilyFilter. Loading a new family, if not already present. Creating a new family symbol, i.e.... Read more →

Compound Wall Layer Volumes

Here I continue the discussion of one of the topics that were raised in the Revit API training in Verona last week. We can combine the two discussion strands analysing wall areas and compound wall layers to calculate the volumes of each individual layer in a compound wall. In our initial idea for implementing this, we thought of making use of the wall area that we calculated ourselves from the appropriate face of the wall's solid geometry. Whatever method we... Read more →

Unit Types and Format Options

Here is a question from Matt Mason and some exhaustive research results by Saikat Bhattacharya of Autodesk on unit types and their format options. To provide some context, UnitType is an enumeration listing all the unit types supported by Revit. The FormatOptions class is used to manage information for the ProjectUnit.FormatOptions property, which returns a FormatOptions instance containing the user's current project unit settings for each UnitType queried. Through the project units and the format options management, each unit type... Read more →

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 →

Units

In the previous post, we noted that the area parameter for a wall had a numerical value of 283.65 on one hand, but a string representation of '26.352 m²' on the other. The reason for these two different values is that Revit internally works with a fixed set of database units for different measurement types. These internal database units cannot be changed. All raw database values obtained from attributes will always be returned and expected in database units. Some of... Read more →