File Formats: STEP File

Description

STEP (Standard for the Exchange of Product model data) is an ISO standard. Geometry is defined mathematically using analytic and parametric surface and curve definitions, such as Non-Uniform Rational B-splines (NURBS). The Strand7 STEP importer considers only geometry data in STEP files, and the exporter exports only geometry data; finite element information is not supported for import or export.

Supported STEP Entities

Strand7 implements STEP application protocols Config Control Design (AP203) and Automotive Design (AP214). Strand7 also accepts STEP files defined using other application protocols, however only entities recognised by AP203 and AP214 are processed. Both long and short entity names are accepted.

The following STEP entities are supported by Strand7:

B_SPLINE_CURVE
B_SPLINE_CURVE_WITH_KNOTS
B_SPLINE_SURFACE
B_SPLINE_SURFACE_WITH_KNOTS
CIRCLE
CONIC
CONICAL_SURFACE
CYLINDRICAL_SURFACE
ELLIPSE
HYPERBOLA
LINE
PARABOLA
PCURVE
PLANE
POLYLINE
QUASI_UNIFORM_CURVE
QUASI_UNIFORM_SURFACE
RATIONAL_B_SPLINE_CURVE
RATIONAL_B_SPLINE_SURFACE
SPHERICAL_SURFACE
SURFACE_OF_LINEAR_EXTRUSION
SURFACE_OF_REVOLUTION
SWEPT_SURFACE
TOROIDAL_SURFACE
TRIMMED_CURVE

Units

Each product/part in a STEP file can potentially be specified with a different set of units. For example, one part could be specified using millimetres, another using inches and another using metres. Strand7 scales all products/parts to the current Strand7 model units. If the STEP file contains units that are incorrectly specified, Strand7 provides options to correct the definition upon import. If the Strand7 model uses no units, geometry data is imported unscaled.

Import/Export Log File Viewer

If warnings or errors are encountered during import or export, a log file is generated and displayed by the View Log File: Log File Viewer. The log file (with extension .LOG) is saved in the same folder as the STEP file; if the folder is a read-only location, the log file is not generated and Strand7 issues a warning message.