When IGES data is exported, it writes lines in a form resembling the database. Each segment on the line becomes a separate curve in IGES. If there is more than one segment in the line, the resulting curves in IGES are joined together with a composite curve entity. NURBS curves and ellipses are written as rational b-spline curves (IGES's rational B-splines are general NURBS).
Surface faces that comprise each surface are written. This allows for output type options. NURBS surfaces are output as rational B-spline surfaces in IGES, as are cones, spheres, and tori. If necessary, curves on parametric surfaces and trimmed surface entities are used to trim the NURBS surface.
The IGES writer uses the iges_writer.ini file with the following available options:
@AuthorName
Value |
Description |
string |
A string to write in the IGES author name field. Default is Unknown. |
@AuthorOrganization
Value |
Description |
string |
A string to write in the IGES author organization field. Default is Unknown. |
@Export
Value |
Description |
all |
Export all geometry (default). |
displayed |
Export displayed geometry only. |
@Layers
Value |
Description |
Layers |
Each component is sent as a different layer (level) in the IGES file. This is the most efficient format (default). |
Groups |
Each component is sent as an associative instance entity (type 402, form 7). |
LayersAndGroups |
Each component is sent as a different layer (level). Each set of faces comprising one surface is sent as an associativity instance (group). |
@OptimizeForCAD
Value |
Description |
on |
Fix gaps between stitched edges and vertices to make the actual geometry of the surfaces consistent with the model topology before export, and check the topology of the model for gaps that are larger than a given tolerance between shared, non-manifold, or suppressed edges. If the gap is found to be bigger than the tolerance, the surface and edge geometries are morphed parametrically and in 3D, if necessary, to make the gap smaller than the tolerance. In addition, non-essential degenerate edges are removed. This also modifies the geometry within HyperMesh (default). |
off |
Do not perform the optimization steps. |
@OuterLoop
Value |
Description |
Optional1 |
The IGES 6.0 standard allows you to default to the natural outer loop of the surface being trimmed. If you are trimming a NURBS surface with several holes and no exterior trimming, the outer loop can be left out of the IGES file, making the surface representation shorter and more accurate. Use this option if it is supported by your IGES post-processor (default). This is not available with the JAMA-IS standard. |
Mandatory2 |
For those post-processors that do not allow an optional outer loop, this option forces an outer loop to be written for trimmed surfaces. |
@Units
Value |
Description |
Microns Millimeters Centimeters Meters Kilometers Microinches Mils Inches Feet Miles <user> |
The unit system to use for export. A custom user-defined value can also be given. |
1The most efficient form is JAMA planes and the Outer Loop Optional option; however, this choice may cause compatibility difficulties.
2To be JAMA-IS compatible, select the JAMA planes and the Outer Loop Mandatory options.