Data Exchange
Data Exchange is a key factor in using Open CASCADE Technology (as well as applications based thereon) concurrently with other software such as CAD systems. It provides the openness of OCCT 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 OCCT-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. |
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What OPEN CASCADE provides for Data Exchange:
Data Exchange interfaces in OCCT allow software based on OCCT to exchange data with various CAD software, thus ensuring a good level of interoperability.;
Data Exchange interfaces function either in accordance with the standards (IGES, STEP), which can be used by various software packages for CAD, PDM etc., or as direct connectors to proprietary formats.
Standardized data covers:
STEP (AP203 : Mechanical Design, this covers General 3D CAD; AP214: Automotive Design)
IGES (up to 5.3)
Data types such as colors, assembly descriptions and validation properties (i.e. center of gravity etc.) are supported. These data are stored together with shapes in an OCAF (XCAF) document.
In addition to standard Data Exchange interfaces, separate components are available to provide direct mapping and data adaptation (using Shape Healing) with CAD software supporting the following formats:
• ACIS SAT
• Parasolid X_T
• DXF
These components are based on the same architecture as interfaces with STEP and IGES.
OCCT includes a module for translating OCCT 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, OCCT 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 OCCT 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.
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.
OCCT includes a module for translating OCCT shapes to VRML (Virtual Reality Modeling Language). OCCT 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 OCCT shapes intended to be written must be solids, components of solids or closed shells with a correct orientation.