Data Exchange

Data Exchange is a key factor in using Open CASCADE (as well as applications based thereon) concurrently with other software such as CAD systems. It provides the openness of Open CASCADE technology in a multi-software environment, by allowing it to process external data and providing a good level of integration.

This means obtaining results of good quality, and covering the needs of exchanges from Open CASCADE-based applications regardless of external data quality or requirements, in particular in respect of allowed data types and arrangements between them, accepted gaps between geometries.

This matter is addressed by Data Exchange Module, which is organized in a modular way, as explained below.

What Open CASCADE provides for Data Exchanges

Data Exchanges in Open Cascade have the following purpose:

to provide tools (connectors), such as Data Exchanges Modules, which allow software based on Open Cascade to exchange data with various CAD software, thus ensuring a good level of interoperability.;

Exchanges function either in accordance with the standards which can be used by various software packages for CAD, PDM etc. (IGES, STEP) or by way of direct connectors which work in proprietary formats or call run-time libraries to access external data.

## Standardized Data Exchange

### STANDARDS

Standardized data covers:

- STEP (AP203 : Mechanical Design, this covers General 3D CAD; AP214: Automotive Design)

- IGES (up to 5.3)

- STL

- VRML

### Translating a shape to STL Format

Open CASCADE includes a module for translating Open CASCADE shapes to STL (Stereolithography) format. STL is a format designed for rapid prototyping. It is intended to send geometric data (volumic) to stereolithography machines, which can read and interpret such data. These machines can transform a volumic model to a physical prototype made of plastic, by using laser to coagulate material, which corresponds to the volume, and set free the material around. STL defines these surfaces by triangles. Thus, no machining is required to switch from a virtual model to a physical one.

Since STL files can only include solids described by their mesh structures, Open CASCADE shapes, which are intended to be written, must be solids, components of solids or closed shells with a correct orientation.

When translating shapes to STL format, remember that all references to shapes mean references to Open CASCADE shapes unless otherwise explicitly defined. In addition, sets of faces or unclosed shells may also be translated but visualization in foreign viewers may be incorrect.

### Translating a shape to VRML Format

The Virtual Reality Modeling Language (VRML) is a language for describing multi-participant interactive simulations - virtual worlds networked via the Internet and hyperlinked with the World Wide Web. VRML is a format designed for animated visualization of solids.

Open CASCADE includes a module for translating Open CASCADE shapes to VRML (Virtual Reality Modeling Language). Open CASCADE shapes may be translated in two representations (states): shaded or wireframe. Since shaded VRML format files include only solids described by their mesh structures, the Open CASCADE shapes intended to be written must be solids, components of solids or closed shells with a correct orientation.

### Extended data exchange (xde)

XDE allows you to adapt the scope of exchange, as an addition to geometric ("BREP") data, thereby improving the interoperability with external software.

Data types such as colors, assembly descriptions and validation properties (i.e. center of gravity etc.), which are handled in OCAF, are supported.

Apart from other benefits of Shape Healing and XDE, Data Exchange module also allows to query and examine a file, results of conversion and its validity. It is designed to support extensions (like new standards) in a common modular architecture.

## Proprietary Data Exchange

In addition, Connectors (optionally available as separate components) provide direct mapping and data adaptation (using Shape Healing) with CAD software in the following modes:

- Euclid-3

- Catia

- ACIS

- Parasolid

- DXF

Connectors are based on the same architecture as exchanges with STEP and IGES.