Web IFC .NET

DEPRECATED: This project is now superceded by the Ara 3D IFC-toolkit

Rationale: we need to run on multiple platforms and C++/CLI is restricted to Windows only.

About

A C++/CLI wrapper around the C++ code powering the Web IFC library originally written by Tom van Diggelen and being developed by That Open Company.

What is C++/CLI

C++/CLI is a variant of C++ that makes it easier to write interoperability code that communicates between C# and C++. This is not unlike how the C++ code is compiled using WASM to be usable from JavaScript.

Why?

Out goal was to significantly improve the IFC import service current in the Speckle server. https://github.com/specklesystems/speckle-server/blob/main/packages/fileimport-service/ifc/parser_v2.js

We wanted to create a project that replicates the behavior of the existing Web IFC library, but with a .NET API, and that can consume updates to the main C++ library as they are made to the Web IFC library.

This project makes it possible to consume the Web IFC library from .NET and allows us to better identify issues and performance bottlenecks.

We can now:

• Quickly create helpful high-level libraries and GUI applications using C#
• Step into and debug the C++ code, even from a C# application
• Quickly create unit, performance, and regression tests using NUnit
• Improve key algorithms with code written in C#

Code and Repository Structure

This repository consumes the Engine Web IFC repository as a sub-module: https://github.com/ThatOpen/engine_web-ifc.

The solution contains three main projects:

• WebIfcClrWrapper
  • this is a C++/CLI project.
  • Only one file (DotNetApi.cpp) contains managed code.
  • The rest of the C++ source files are referenced directly from the Web IFC library submodule
• WebIfcDotNet
  • This is a C# project that contains additional data types and algorithms to facilitate working with the .NET API
  • The ModelGraph class provides a high-level interface to an IFC file as a graph of nodes and relationships
  • It was designed specifically to address the needs of the Speckle project
• WebIfcDotNetTests
  • This is a C# project that contains unit tests for the WebIfcDotNet project
  • It uses NUnit as the testing framework

There are temporarily two references to projects, which are not included and are not required.

• Ara3D.Speckle.Data
• Ara3D.Speckle.Wpf

These projects were part of an entry to the Speckle hackathon 2024: https://github.com/ara3d/speckle-desktop

Acknowledgements

This work is sponsored by Speckle.