IfcSharpLibrary

The C#-Library of IfcSharp contains interfaces to the IFC-model of buildingSMART, which is described here.

Introduction

Create a simple IFC file

The creation of an IFC file requires only a few lines of code. The underlying class model has the same structure as the IFC data model and therby enforcing the definitions of the corresponding IFC Schema (2X3, 4.0 etc.) The advantage of this early-binding approach is that errors in an IFC model can be handled at compile time rather than at runtime (late-binding).

// create a new ifc.Model which stores all ifc.ENTITY data inside the ifc.Repository.CurrentModel
ifc.Repository.CurrentModel = new ifc.Model(Name: "hello_project_output"); 

// create a new ifc.Project, this implicitly appends the ifc.ENTITY to ifc.Repository.CurrentModel 
// NOTE: every ifc.ENTITY has an EndOfLineComment which can be used as a comment for STEP files
ifc.Project project = new ifc.Project(Name: new ifc.Label("my first ifc-project"), EndOfLineComment: "creating the project");

// IfcSharpLibrary also takes care of creating the GlobalId if you simple pass 'null'
ifc.Building building = new ifc.Building(GlobalId: null, Name: new ifc.Label("my first ifc-building"));

// due to reflection ifc.ENTITY objects which have no parent dont need to be assigned it to a variable
new ifc.RelAggregates(RelatingObject: project, RelatedObjects: new ifc.Set1toUnbounded_ObjectDefinition(building));

// write the current state of the ifc.Repository.CurrentModel to a STEP file
// the output path defaults to ifc.Model.Name (in this case 'hello_project_output.ifc')
ifc.Repository.CurrentModel.ToStepFile();

Several IFC versions are supported (see Supported IFC Schemas). All IFC versions use the same read and write routines. The read and write routines use the Reflection mechanism. This avoids that for each class a separate read or write routine must be kept. The IfcStep export therefore comprises only a few lines of code, since it evaluates the IFC schema mapped in the C# class library in a general valid manner via Reflection.
This mechanism is also used to keep track of all ifc.ENTITY instances in memory and write them to a file or database. This means that once you assigned a ifc.Repository.CurrentModel at runtime you can just instantiate objects from anywhere in your project. This makes IfcSharpLibrary a very sleek solution as it is reduces the overhead of assigning every single ifc.ENTITY to its parent.

Export capabilities

With the IfcSharp Library you can write IFC-models by C#-code or read and write to different formats, like this:

ifc.Repository.CurrentModel.ToStepFile();  // creates hello_project_output.ifc (step-format)
ifc.Repository.CurrentModel.ToHtmlFile();  // creates hello_project_output.html in step-format with syntax highlighting
ifc.Repository.CurrentModel.ToCsFile();    // creates hello_project_output.cs with c# code (useful for creating code from existing files)
ifc.Repository.CurrentModel.ToSqliteFile();// creates hello_project_output.sqlite3 with the default option exportCompleteSchema=false 
ifc.Repository.CurrentModel.ToXmlFile();   // creates hello_project_output.ifcXml
ifc.Repository.CurrentModel.ToSqlFile();   // creates SQL for ifcSQL without server-connection
ifc.Repository.CurrentModel.ToSql(ServerName: System.Environment.GetEnvironmentVariable("SqlServer"), 
                                  DatabaseName: "ifcSQL",
                                  ProjectId: 3,
                                  WriteMode: ifc.Model.eWriteMode.OnlyIfEmpty); // SQL server connection required

One of these Formats is ifcSQL, that ist not intended to transport Models form A to B. It is instead intended to store and query models as a collection of digital twins (see IfcSql documentation).

Further examples

Please refer to examples listed in IfcSharpApps

Implementation details

General structure

IfcSharpLibrary can be broken down into three different components:

IfcSharpCore: Implements general functionality (i.e. types, units, logging etc.)
IfcSchema: Implementations for the different IFC schemas as C# classes (see IfcSchema documentation)
IfcIO: Currently we support STEP, SQL, SQLite, CS, HTML and XML (some implementations are still in need for further development and testing)

This makes this library highly customizable and enables you to choose specifically which implementations you need.

Supported IFC Schemas

We currently support these IFC schemas:

IFC2X3
IFC4
IFC4.1
IFC4.2 (now part of IFC4.3.2.0)
IFC4.3.2.0

NOTE: Due to the class model you can only include the IfcSchema for one IFC version. This means for multiple IFC versions you need to create multiple build-projects.

How to Install and Run the Project

Simply run git clone https://github.com/IfcSharp/IfcSharpLibrary.git.

To start off you can directly add a reference to the included IfcSharpLibrary.csproj file, which is configured to use the IFC4 bindings.

NOTE: The default IfcSharpLibrary.csproj project does not include the optional SQLite support. In order to use it you have to install the additional dependencies and include the files from IfcIO/IfcSqlite in your project (see also IfcSqlite README ).

After you included/created the project the ifc namespace should be available and you can start developing with IfcSharpLibrary.

Optional: IfcSqlite

See IfcSqlite documentation

Credits

Bernhard Simon Bock @bsbock
Friedrich Eder @friedrichEder

Licence

This project is licensed under the terms of this MIT license.

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