STEP file - information about STEP file format (ISO 10303)

"STEP" stands for "Standard for the Exchange of Product model data" and is the informal name for ISO 10303. ISO 10303, i.e. the STEP file format, is an international ISO standard for the computer-interpreted representation and exchange of information on manufacturing products. The official name is: Automation Systems and Integration - Product data representation and exchange. ISO 10303 can represent 3D objects and related information in computer aided design (CAD) systems.

International standard

The ISO technical committee TC 184 develops and maintains the STEP format . Like other ISO and IEC standards, the STEP file is subject to ISO copyright and a fee is charged.

Because of ISO standardization, Step is perfect for exchanging data between different systems. Typically, a Step file (also referred to as a .stp file) is used to exchange data between CAx systems such as CAM (computer-aided design and manufacturing) and CAE (computer-aided engineering) processes, in business data modeling and other computer technologies.

Open STEP file

As explained earlier, the main functionality of a STEP file is to make its contents readable by a wide variety of different software environments. This standard makes it possible to view three-dimensional graphics and product definitions in different applications. You can open a .step or .stp file with different applications, such as STEP Viewer or IDA STEP.

This flexibility in opening, converting and creating STEP files allows easy exchange of product data, mechanical and electrical design, 3D dimensions and tolerances, analysis and manufacturing data specific to different industries (for example, automotive and aircraft and many more).

Development of STEP

The foundation of STEP was the Product Data Exchange Specification (PDES), which was launched in the 1980s and introduced to ISO in 1988. The Product Data Exchange Specification was an attempt to define data in order to improve communication between companies and thus increase productivity.

The development of STEP can be divided into several phases. STEP was originally intended to be based on a single comprehensive and implementation-independent product information model. However, due to the complexity of the subject, the standard had to be broken down into several parts, revised and released. In 1994/1995, ISO published the very first version of STEP.

Configuration-Driven 3D Design was an important part of Step files until 2014 (when it was replaced by AP 242). A STEP file is supported by many CAD systems for both import and export. The STEP format is also abbreviated as .step or .stp.

The second development phase of the STEP file

In the second phase the functionality of STEP was extended especially for the product development in the aircraft, automotive, electrical industry. This phase ended in 2002 with a second main version, which included a part of STEP AP 202, AP 209, AP 210, AP 212, AP 214, AP 225, AP 227, AP 232. Especially in the geometric area, harmonization between APs was achieved by introducing constructs that are interpreted by the application (AIC, 500 series). The abbreviation "AP" stands for application protocols. They are packages of data types and interfaces that are available for different application areas and extend the functionality of Step. The number following AP describes the type of protocol.

STEP 3 - The third development phase

The main problem with the APs of versions 1 and 2 is that they are too large. They have too much overlap and are not consistent enough. This activity was carried out for the development of new APs that cover new phases of the product life cycle. Examples include the early needs assessment (AP 233) and new industry areas (AP 221, AP 236.). Based on this modular approach, new versions of previously monolithic APs were developed (AP 203, AP 209, AP 210). In this way it turns out to be very easy to transform the STP file.

Each AP is tailored to the product type or sales scenario. STEP defines data models with the modeling language EXPRESS and SysML. Application data related to the data model can be exchanged via a STEP file, a STEP XML file, or database sharing through an SDAI.

AIM and MIM

Each access point defines a data model which is used for communication and is called Application Interpretation Model (AIM) or in case of Modular AP Module Interpretation Model (MIM). One creates these models by selecting common objects from low-level data models (parts 4x, 5x, 1xx, 5xx) and adding the necessary specializations for the PA application. An additional data model called domain model (DM) is not necessarily present to implement exchange or service processes closer to business concepts and based on XML. Initially, each AP was accompanied by an abstract test suite (ATS), such as ATS 303 for AP 203. This provided test objectives, acceptance criteria, and abstract test models, as well as STEP sample files. The first APs were documented unofficially with IDEF1X diagrams. As AP became more complex, formal methods for documenting ARM were needed. In addition, EXPRESS, which was originally intended only for AIM development, was also used for ARM.

FAQ about the STEP file

What is a STEP file?

STEP stands for "STandard for the Exchange of Product model data" and is an international ISO standard for the computer-interpreted representation and exchange of information about manufacturing products. A STEP file conforms to this standard, usually contains three-dimensional graphics, and includes information about the functional aspects of the product in addition to the physical data.

How do I open a STEP file?

A STEP file allows three-dimensional graphics and product definitions to be viewed in various applications. A .step or .stp file can be opened using various applications, such as STEP Viewer or IDA STEP.

Can an STP file be converted to a Dwg file?

A step file can be easily converted to a Dwg file and several other formats (e.g. iges).

What is the purpose of ISO 10303?

The purpose of this international standard is to provide a mechanism capable of describing product data throughout its lifecycle (or a particular application).