Globally, open source has become an important model for software technology and industry innovation. Software such as Linux, Android, and MySQL has adopted open source strategies, while the number of global open source software projects continues to grow steadily. According to data from GitHub, the world’s largest code hosting platform, as of 2023, GitHub hosted repositories have reached 420 million, with 73 million new repositories added, a growth rate of 21%.
Proponents of open source firmly believe that the open source model, compared to the closed patent development model of the industrial era, is more in line with the fast iteration and wide application scope of technology in the digital age. It stimulates the innovation and creativity of various entities through decentralized collaboration, achieving wisdom accumulation through open collaboration, greatly improving innovation efficiency and quality.
In recent years, the internationalization of the open source ecosystem for industrial software has deepened, and the construction of the open source system has transitioned from a stable start to a new stage of accelerated development. Relying on the open source model for accelerated development has become an important choice for emerging industrial software vendors and a key path for promoting innovation in industrial software.
So, what open source engines exist in the field of industrial software R&D? Which open source projects are developing well? What opportunities and challenges do they face? How is the Chinese market positioned and progressing in this field? This article will analyze and introduce these aspects one by one.
Observations on the Open Source Ecosystem of Industrial Software
1. The Foundation of a Skyscraper: Starting from the Geometric Modeling Kernel
The geometric modeling kernel is a software component that provides modeling functions in CAX software and is the cornerstone of any CAX software. It defines the expression and design interaction capabilities of modeling shapes, defines the language of geometric shapes, and encompasses the data structures and corresponding algorithms of mathematical, geometric, and topological objects; as well as file import/export functions that can import IGES models, STEP models, and other standard file formats, and can uniformly convert to proprietary file formats.
Over the 60-year development history of CAX, dozens of kernels/platforms have emerged. Among them, the most famous in the two-dimensional field is ITC (IntelliCAD Technology Consortium). IntelliCAD is fully compatible with AutoCAD, not only in interface, command set, and file format but also in programming interfaces LISP and SDS (C++), which are also compatible with AutoCAD. This has led to many paying members in the ITC technology alliance;
In terms of standard compatibility in the two-dimensional field, it mainly relies on ODA (Open Design Alliance). The ODA is a non-profit technology alliance composed of 1,200 member companies. It is well known that the two industry standards for two-dimensional CAD software—the DWG data standard and the ARX secondary development standard—are formulated, updated, and maintained by Autodesk, and member companies that join the ODA alliance can obtain technical authorization from ODA to be compatible with the DWG data standard.
Figure 1: The Relationship Between AutoCAD, ITC, and ODA
Thanks to the golden combination of ITC + ODA, a number of influential software such as ZWCAD, Wrightsoft, progeSOFT, FRAMECAD, CADian, ActCAD, and MicroSurvey have emerged.
In the three-dimensional field, the three most representative kernels are—ACIS (acquired by Dassault), Parasolid (acquired by Siemens Digital Industries Software), and OpenCasCade (an open-source geometric modeling kernel). Additionally, with the development of CAX technology, more and more companies are exploring their own kernel (Own kernel) development paths, such as PTC’s Granite, CATIA’s CGM, and SOLIDWORKS gradually shifting to CGM, CrownCAD’s DGM kernel, ZW3D’s Overdrive kernel, etc.
Table 1: Globally Known CAD Kernels/Platforms
(Source: e-works, selecting some representative kernels/platforms)
Among them, ACIS was originally developed by Spatial Technology, Inc. (later acquired by Dassault Systems), and is a geometric platform used for CAD system development. It provides modeling functions from simple solids to complex solids, as well as various editing functions such as Boolean operations, surface trimming, and surface transitions, and also provides data storage functions for solids and SAT file input and output functions.
The characteristic of ACIS is that it adopts an object-oriented data structure and is programmed in C++, allowing for flexible combinations of line frame modeling, surface modeling, and solid modeling. ACIS products use software component technology, allowing users to use the required components or replace ACIS components with their own developed components. Representative software using the ACIS kernel includes AutoCAD, ABAQUS, Fluent, Nastran, Cimatron, SpaceClaim, REVIT, ActCAD, etc.
Parasolid, developed by Shape Data, is now owned by Siemens Digital Industries Software and can be licensed by other companies for their 3D computer graphics software products. Parasolid’s functions include model creation and editing utilities, such as Boolean modeling operations, feature modeling support, advanced surface design, thickening and hollowing, blending and slicing, and drawing modeling.
Parasolid also includes tools for direct model editing, such as gradual thinning, offsetting, geometric replacement, and removing feature details by automatically regenerating surrounding data.Parasolid also provides extensive graphics and rendering support, including hidden lines, wireframe and drawing, surface subdivision, and model data queries. Representative software using the ParaSolid kernel includes NX, SolidEdge, SOLIDWORKS, ANSYS, Onshape, FEMAP, Adams, Adina, Shapr3D, etc.
2. A Collection of CAX Open Source Software/Projects, OCC Leads the Pack
For decades, with technological evolution and innovation, the CAX kernel has not shown a pattern of multiple blooms but has instead formed a duopoly of ACIS and Parasolid. Although many companies are exploring their own kernel development paths, it is challenging to form a scaled challenge.
This has also made open source another choice besides ACIS, Parasolid, and Own kernel.
We must mention Open CASCADE (Open Computer Aided Software for Computer Aided Design and Engineering), which is one of the world’s most important geometric modeling foundational software platforms and the only open-source geometric modeling engine with engineering value in the industrial field.
The history of Open CASCADE can be traced back to the 1980s with Matra Datavision, when Matra Datavision released the Euclid CAD system, gradually becoming a market leader in the CAD/CAM field with version iterations. In 1993, Matra Datavision created a development platform called CAS.CADE (Computer Aided Software for Computer Aided Design and Engineering), and in 1999, it released the CAS.CADE development platform as open source under the name Open CASCADE; in 2000, Matra Datavision announced the establishment of a subsidiary called Open Cascade SAS; thereafter, after several mergers, the Open Cascade platform was renamed Open Cascade Technology (OCCT) to avoid confusion with the company’s name (Open Cascade).
In geometric modeling, Open CASCADE is a powerful 3D modeling tool that provides display and interaction operations for points, lines, surfaces, solids, and complex shapes. After deep development, it can achieve graphics operations such as texture, lighting, primitive filling, rendering, and dynamic operations such as zooming, rotating, roaming, simulated flight, and simulated traversal; in data exchange, Open CASCADE provides advanced tools for CAD data exchange, supporting common formats such as STEP, IGES, STL, and VRML; in visualization, the Open CASCADE Technology platform provides a customized visualization subsystem based on OpenGL, which not only allows effective use of the library’s geometric resources but also supports interactive 3D scenes in real CAD applications.
In business models, Open CASCADE allows software developers worldwide to use its technology through an open-source approach, and its “open source” attribute is well known to the public. Today, there are many open-source projects/software based on the Open CASCADE engine, as well as open-source communities built on Open CASCADE.
Table 2: Globally Known CAX Open Source Engines and Projects
(Source: e-works, selecting some representative open source kernels and projects)
In addition to Open CASCADE, CAD open source engines also include Coin3D and CGAL. Coin3D is an open-source cross-platform library for 3D graphics programming, usually used in conjunction with Open Inventor (a standard and toolkit for 3D graphics development); CGAL is an open-source computational geometry algorithm library, although it is also applied in the CAD field, such as the open-source project Open SCAD that uses CGAL for constructing solid geometry (CSG) evaluation. However, CGAL is more commonly applied in geographic information systems (GIS), computer graphics (CG) (games, entertainment, etc.), as well as molecular biology, medical imaging, and other fields.
In the simulation analysis field, open source engines mainly include OpenFOAM, CodeAster, SU2, Calculix, etc. OpenFOAM is a free open-source CFD software developed by OpenCFD Ltd since 2004, releasing a professional version every six months, including customer-sponsored development and contributions from the community. After multiple mergers and reorganizations, OpenFOAM is now a wholly-owned subsidiary of ESI Group, which was acquired by Keysight in 2023.
CodeAster is an open-source finite element simulation software suitable for physical phenomena such as solid mechanics, thermodynamics, and acoustics, specifically subdivided into statics, dynamics, fluid-solid coupling, and heat transfer, originating from the French Electric Power Group (EDF), and currently operated by a multinational team of experts from Germany, France, and Austria.
SU2 is a collection of open-source software tools written in C++ and Python for analyzing partial differential equations (PDE) and PDE-constrained optimization problems on unstructured meshes using advanced numerical methods, widely applicable in the aerospace, automotive, marine, and renewable energy industries. It originated from the Aerospace Design Lab (ADL) at Stanford University’s Department of Aeronautics and Astronautics and is currently operated by the SU2 Foundation.
Calculix is an open-source structural finite element software developed by engineers from MTU Aero Engines in Munich, Germany, distributed under GPL, with the processor and solver available for standalone use and providing external CAD interfaces.
Additionally, there are a number of successful CAX open-source projects that share a common characteristic: they are built on the Open CASCADE open-source geometric modeling engine or constructed on multiple free open-source software libraries:
For example, FreeCAD is an open-source CAD/CAE tool based on OpenCASCADE. FreeCAD has functions similar to CATIA, SOLIDWORKS, and Solid Edge, and thus also provides product data management functions beyond CAX. It is also multi-platform, able to run on Windows, Linux/Unix, and Mac OSX;
SALOME is an open-source CAE integration platform with multi-party cooperation, jointly initiated by EDF, the French Atomic Energy and Alternative Energy Commission (CEA), and Open CASCADE; SALOME’s main functions include geometric modeling, mesh generation, and post-processing, where geometric modeling is based on Open CASCADE, mesh generation is mainly based on NETGEN and Gmesh, and post-processing is mainly achieved through ParaView;
The open-source domestic CAE software integration development platform FastCAE also has its geometric modeling template based on Open CASCADE, incubated by the Open Atom openCAX industrial software working committee, providing a rapid development integration framework for CAE software interfaces and general function modules for solver developers, allowing users to use it for free while encouraging commercialization;
Open Geometry is a newly established open-source community in China in 2023, based on Open CASCADE, incubated by the Digital Industrial Software Alliance, and operated by Kaiyuan Geometry as a service company, mainly building a “cloud geometric kernel open-source software development platform”.
Other open-source projects include the cloud-based CAM open-source project Open Builds CAM, suitable for five-axis laser processing and other CNC machining operations; and Feature Script, which originated from Onshape, mainly used for creating and processing 3D parametric models. The Feature Script is built into Onshape, and its source code is open-source, available for free viewing in a public Onshape document named “std”.
Opportunities and Challenges for Open Source Industrial Software
1. Opportunities Ahead: Open Source Accelerating Innovation is a Consensus
Looking at the development of the global open-source ecosystem, it shows an increasingly prosperous trend compared to previous years:
First, in terms of technological innovation, open source has the characteristic of gathering wisdom and promoting multi-party collaboration, which can effectively enhance the speed of technological innovation and breakthroughs in major scientific problems; second, in terms of industrial development, by absorbing the collaborative model of open source cooperation, the division of labor chain becomes longer and broader, allowing more talents in the industrial chain to participate in scenario-based and customized application needs, achieving co-creation; in terms of cooperation, open source can link extensive international cooperation relationships and build a closer global collaborative division of labor system.
From a broad perspective, this new collaborative model of openness and sharing is a key driving force for innovation, openness, sharing, and sustainable development in the digital economy. Compared to the closed industrial system driven by patents in the industrial era, it features higher division efficiency and broader collaboration scope. It can be said that open source accelerating innovation has become a basic consensus in the industry.
Of course, for the industrial software field, leveraging open source does not necessarily mean overtaking on curves, but it can stir up some waves in a long-firm market or occupy a place in niche markets.
Take the ITC technology alliance as an example. Although it is a paid membership alliance, it has developed influential software such as ZWCAD, Wrightsoft, progeSOFT, FRAMECAD, ActCAD, and MicroSurvey based on IntelliCAD. For instance, Wrightsoft has become a global leader in the HVAC design field, while ZWCAD provides products and services to over 1.4 million users in more than 90 countries and regions.
Based on Open CASCADE, a number of representative open-source projects and products have emerged, covering numerous industries and fields such as aerospace and defense, automotive, BIM and AEC, chemicals, consumer goods, dentistry, electronic engineering, industrial equipment, mechanical engineering, medical, military, shipbuilding, robotics, special machinery, and sporting goods.
2. Challenges Persist: Potential Risks Facing Open Source
On the other hand, while open source code provides great convenience for industrial software development, it also comes with many challenges.
In addition to conventional open-source risks such as code vulnerabilities and supply chain attacks, a greater challenge for industrial software open source is to comply with the corresponding open-source regulations of the software. Under the open-source model, different licenses have varying requirements for software redistribution, which is crucial for software developers selecting open-source software. A slight misstep could lead to pitfalls or even incur high costs.
Typically, open-source licenses fall into three categories: the first allows secondary closed-source distribution, requiring the original copyright and license notice to be retained, with representative license models including MIT, Apache 2.0, BDS 2.0-clause, etc.;
The second allows secondary closed-source distribution under certain conditions, with common license models such as LGPL 2.1, which permits commercial software to be closed-source through code library references (with software code loosely coupled with referenced source code);
The third does not allow secondary closed-source distribution. Common license models such as GPL—its version 2.0 does not allow closed-source distribution, while version 3.0 imposes stricter open-source requirements.
The Jiushou CAX kernel from the University of Science and Technology of China insists on independent research and development without choosing open source, mainly due to concerns about the restrictions of the GPL license model.
Currently, most industrial software that chooses open source is developed based on the Open CASCADE kernel, and they all need to be released under the LGPL License model. LGPL is a variant of GPL (GNU General Public License) that allows the use of LGPL code without opening the entire project’s source code. It is primarily used for software libraries, allowing linkage with closed-source software without mandating open-sourcing, but modified LGPL code must still be disclosed.
This means that companies releasing their commercial software based on Open CASCADE open-source code need to publicly disclose and release the modified portions of the code, or they may face copyright infringement lawsuits.
In fact, in the industrial software field, disputes and controversies arising from source code are numerous. Different open-source licenses impose different levels of open-source requirements for secondary distribution, and the stricter the requirements, the harder it is for developers to protect the confidentiality of commercial version releases. Balancing intellectual property and infringement risks is a significant challenge for industrial software to embrace open source!
The Rapid Development of China’s Open Source Industrial Software Industry
1. Policy Support Accelerates Open Source Construction in Industrial Software
With the continuous development of open-source technology, European and American countries have gradually improved their open-source policies, which play a positive role in encouraging innovation, promoting technology sharing, and protecting open-source communities.
Figure 3: Summary of Open Source Policies in European and American Countries (Source: e-works)
In the past two years, China’s open-source support policies have been continuously implemented, to some extent promoting the construction of the industrial software open-source system from a stable start to a new stage of accelerated prosperity.
The “14th Five-Year Plan” and the 2035 Vision Outline compiled by the State Council mention the support for the development of digital technology open-source communities and other innovative coalitions, improving the open-source intellectual property and legal systems, and encouraging enterprises to open software source code, hardware designs, and application services; the Ministry of Industry and Information Technology’s “14th Five-Year Plan for the Development of Software and Information Technology Services” clearly states the need to cultivate key open-source projects, build excellent open-source communities, and enhance open-source governance capabilities.
Local governments have also frequently introduced related policies to support open source:
In the implementation plan issued by the General Office of the Anhui Provincial People’s Government titled “Promoting the High-end, Intelligent, and Green Development of Manufacturing through Digital Transformation (2023-2025)”, it is proposed to support the construction of the industrial software open-source ecosystem.
The General Office of the Qingdao Municipal People’s Government issued the “Digital Qingdao Action Plan for 2023”, proposing to encourage leading enterprises in the industry to build open-source platforms, incubate a batch of foundational and forward-looking open-source projects, and accelerate the construction of an open-source software ecosystem.
The Wuxi Municipal People’s Government issued the “Three-Year Action Plan for the Development of the Wuxi National Sensor Network Innovation Demonstration Zone (Wuxi IoT Industry Cluster) (2023-2025)”, mentioning the need to deepen cooperation with domestic open-source foundations, code hosting platforms, and open-source communities.
The General Office of the Beijing Municipal People’s Government issued the “Action Plan for the Innovative Development of the Robotics Industry in Beijing (2023-2025)”, mentioning the need to vigorously promote the research and application of open-source control systems, open-source chips, and open-source simulation software.
The Jiangsu Provincial Department of Industry and Information Technology issued the “Three-Year Action Plan for Accelerating the Development of Open Source Software (2023-2025)”, emphasizing the need to support specialized exemplary software colleges to play a leading role in cultivating open-source talent and explore integrated open-source talent training models.
In December 2023, the General Office of the Jiangsu Provincial People’s Government issued “Several Policy Measures to Accelerate Independent Innovation in Industrial Software”, mentioning the support for open-source technology innovation. It encourages various regions to establish and attract independent open-source software innovation platforms, support the operation of open-source communities based on independent foundational software, hold open-source technology exchange activities, and establish an open-source software project “whitelist” system to create an open-source and open technology product innovation and application ecosystem.
In July 2022, under the guidance of the Open Atom Open Source Foundation, China also established the Open Source Industrial Software Working Committee (Open Atom openCAX), dedicated to building an international open-source industrial software toolchain, promoting the orderly development of China’s open-source ecosystem, accelerating the accumulation of key core technologies in industrial software, and the iterative commercialization of the industry, providing an international exchange platform for users, developers, and researchers of open-source industrial software. Open Atom openCAX has formed 10 SIG technical groups by gathering domestic open-source industrial software forces and is planning to establish China’s first open-source industrial software community to conduct open-source industrial software technology research and actively promote the culture of open-source industrial software.
2. Tasting the Crab: Exploring the Development of Domestic Open Source Industrial Software
In exploring the development of open-source industrial software, there is a group of pioneers who are brave enough to try, driving the development of China’s open-source industrial software.
2.1. FastCAE Project Led by the Open Source Industrial Software Working Committee
The traditional CAE software development method usually involves CAE vendors/R&D units designing architecture from scratch and gradually developing corresponding functional modules. This results in a considerable time cycle, high technical talent requirements, and high costs.
Over the past few decades, some universities and research institutes in China have made many explorations and accumulations in CAE solvers and CAE software productization. How to make their work synergistic and realize scaled value? The FastCAE open-source project led by the Open Source Industrial Software Working Committee (Open Atom openCAX) is currently exploring this.
The initiation of the FastCAE project aims to create an open-source model for a CAE software integration framework platform, integrating key technologies of CAE software and participating entities to form an open, shared, and collaborative R&D and application ecology. This can address two key issues:
First, it liberates low-value, repetitive work in the CAE development process for high-value CAE software co-creation; second, it insists on open-sourcing common technologies at the base level and explores a phased open-source revenue business model.
It can be said that after four years of accumulation, FastCAE has achieved a certain degree of collaborative development in business, technology, and talent. This includes organizing open-source academy training, open-source industrial simulation software integration competitions, and multiple thematic speeches and promotions, applied in industries and fields such as shipbuilding, automotive, aerospace, nuclear energy, machinery, thermal energy, and multi-field coupling, serving over 100 instances of domestic CAE software, covering more than 40 units including universities, research institutes, and enterprises.
Of course, FastCAE still has a long way to go in terms of business model. Only by truly developing into a competitive and viable commercial product can it stand in the market.
2.2. OGG Open Source Project Incubated by the Digital Industrial Software Alliance
In 2022, due to the sanctions against Russia caused by the Russia-Ukraine conflict, it involved the Open CASCADE open-source geometric modeling engine created by a French company. With the OCC’s original community ceasing cooperation with the Russian community, the community’s work was paralyzed, and technical updates and code maintenance stopped. Against this backdrop, Huawei took over the OCC’s Russian community, integrating most of the R&D personnel into Huawei’s Russian research institute, thus restoring the technical maintenance and code update work of the OCC Russian community.
Subsequently, Huawei, in compliance with the original community’s licensing, migrated all source code of the OCC Russian community to Huawei’s cloud server.
This is the background for the establishment of the Open Geometry Group (OGG) open-source community. To distinguish it from the original Russian community name, in 2023, the Open Geometry Group (OGG) open-source community was officially named and established under the leadership of the Digital Industrial Software Alliance.
In April 2024, the OGG 1.0 open-source geometric modeling engine was officially released. Over the past two years, Huawei’s technical team has made 486 enhancements to OGG and continues to update and develop. In the future, OGG will also plan to focus on the new generation of cloud geometric fusion kernels, open-source test case libraries, CAD model interaction standards, and more.
Unlike the FastCAE open-source project that focuses on the CAE field, OGG covers a broader range of fields and categories. From a technical perspective, OGG has received 12 veterans from the Open CASCADE founding team and has formed a multinational geometric algorithm team of more than 50 people, demonstrating its commitment to open source; however, OGG also faces challenges in its business model, as it can only sustain itself in the long run by winning the market in a commercial way.
Postscript
Discussing the development of open-source industrial software first requires clarifying several concepts:
First, open-source software allows users to freely access the source code under the condition of complying with licensing restrictions. Complying with open-source rules and regulations is crucial; otherwise, one may fall into pitfalls and incur high costs;
Second, open source is a development philosophy and approach, and it does not mean free. Open-source software also faces commercialization issues, and without sufficiently competitive business models, it may be short-lived and become a fleeting phenomenon.
In general, we should have the courage to embrace open source and encourage those pioneers who attempt, explore, and even make mistakes with open source. Based on the open-source model, they will contribute years of insights, experiences, and know-how, which is itself an initiative that aligns with the values of digital economy and facilitates the formation of a closely-knit global pattern and sustainable development.
However, at the same time, it is essential to have a clear understanding and judgment of the challenges and risks faced by open-source industrial software, as well as the long-term investments and competitive business models required. On this basis, leveraging open source to reduce the cost of developing industrial software, achieving globalization in use, iteration, error correction, and sharing may very well be a differentiated path for innovation and development in industrial software!