VDAIS export options

VDAIS format is a subset of the IGES standard.

Tip

Spline Type, Output Style, Surface Type and Rebuild Geometry are automatically set to the appropriate values when you select a specific vendor from the vendor list. See Common File Format Descriptions page 44 for more information on the By Vendor window.

Spline Type

Lets you choose between B-spline or parametric forms of curves and surfaces to be created in the VDAIS file.

For B-SPLINE, curves are written as NURBS curves (entity 126) in VDAIS and surfaces as NURBS surfaces (entity 128). This is the default.
For PARAMETRIC, curves are written as parametric curves (entity 112) and surfaces as parametric surfaces (entity 114).

The PARAMETRIC option does not support high degree or rational geometry. When using this option, any high degree and/or rational geometry is automatically rebuilt to be, at most, cubic and non-rational.

Output Style

Converts surfaces to curves for some drafting packages. If you choose to convert surfaces to curves and have set the patch precision to a number greater than the default, all isoparametric curves are stored in the file.

The default is PRESERVE SURFACES.

Surface Type

Determines whether trimmed surfaces are written as trimmed or bounded. The default is TRIMMED SURFACES.

For TRIMMED SURFACES, trimmed surfaces in the modeler are written as trimmed surface entities (entity 144) and (trim) surface curves are written as curve on surface entities (entity 142) in the VDAIS file.

Level Mapping

Determines the type of Alias information exported as VDAIS Level information.

For LAYER, Alias Layer number information associated to each entity is exported as IGES Level information in the Directory Entry of this VDAIS entity in (field number 5). In this case, Alias SET information is ignored and not exported to VDAIS.

For SET, Alias Set information is exported as IGES Level information. If an Alias Set is given a name of the form LEVEL<n>, where <n> is an IGES level number and greater than 0, then the corresponding VDAIS entity for each member of the Alias Set is assigned to level<n> in the VDAIS file.

For example, the VDAIS entities corresponding to each member of the set LEVEL42 are assigned to level 42 in the VDAIS file. Alias Multi-sets information is exported as VDAIS (type 406, form 1) Property entity definition levels. If an Alias object is a member of several multi-sets that conform to this naming convention, then the VDAIS file contains a Property Entity 406 form 1 (Definition Levels) listing the VDAIS levels to which the corresponding entity belongs. In this case, Alias Layer information is ignored and not exported to VDAIS.

Include Comments

Determines whether or not comments entered in the Edit File Comments section (found in the VDAIS File Header Information window) are included in the exported file. The default is OFF. See File Header Information page 46 for details.

Rebuild Geometry

When set OFF (the default), the degree of the resulting surface and the weights on the CVs do not change.

When set ON, models are updated so that all curves and surfaces are compatible with CAD systems or neutral file formats that cannot fully support NURBS geometry by:

Reducing high degree curves and surfaces to degree 3.
Making non rational curves and surfaces where rational ones existed before.

The resulting curve or surface is forced to be at most degree 3, with the weight of all CVs equal to a value of 1.0.

For example, if your model contains curves or surfaces that are rational (with some weights that are not equal to 1.0) or high degree (higher than cubic or bi-cubic), then it is sampled at a number of checkpoints and the data is fit with a cubic or bi-cubic, non-rational curve or surface. Knots are inserted until the fit is within the specified tolerance.

Scale Factor

Lets you save the wire model at a scale other than it was constructed. 1.0 is the default value.

Significant Digits

Lets you specify the number of significant digits for coordinate data in the exported file. The minimum number is 1 and the maximum number is 15.

Filename Extension

Some receiving systems require that CAD files have a specific filename extension before they can be recognized. This filename extension specified is automatically appended to the filename of the exported file. The default is.iges.

Note

There is no Output Units option for VDAIS because coordinate data exported to VDAIS files are always in millimeters, regardless of the linear units set in Alias. This is a requirement of the VDAIS standard.

VDAIS File header information

If you choose the VDAIS file format, the Save Options window expands to display the following:

Edit File Header: When you click this field, a File Header Information menu is displayed with fields specific to the file format you’ve chosen. Use these fields to communicate information about the model being exported and the sender and receiver of the data. This information is exported in the file header of the file.

These fields are optional.
Edit File Comments: When you click in this field, an editor window is displayed where you can type comments specific to the file you are saving. This editor window can be specified in the General section of Preferences > General Preferences.

Common file format descriptions – VDAIS by Vendor

To choose the specific software product to which you are transferring your model, open the VDAIS by Vendor section.

When you choose a specific vendor, your output file is customized to optimize data exchange for the target system. The data exchange parameters (output environment variables) are modified. The active vendor is highlighted.

You can create new vendor files or remove files (except the default) and the By Vendor window is updated accordingly.

Note

The system does not recognize a vendor file without an appropriate header. Create a new vendor file by copying, renaming, and modifying an existing one.

Note

An appropriate header has the text “Vendor Configuration File” followed by a number sign (#) and the vendor’s name. It is important to note that the placement of the vendor’s name must follow the space after the number sign (#) on the first line.