Importing ACIS Files

To import an ACIS file:

  1. Select File and then Import.
  2. Select the file to be imported.
  3. Select ACIS from the Files of type drop-down menu.
  4. Click Open. A new window will appear.
  5. Optionally specify any appropriate settings from this window.
  6. Click Finish.

Import Acis '<acis_filename>' [No_bodies][No_surfaces] [No_curves][No_vertices][Group {'<name>'|<id>}] [Binary|Ascii] [Show_Each] [Sort] [Attributes_On] [Separate_Bodies] [merge_gloabally] [Heal]

The import ACIS command is the primary mechanism for generating geometry within Trelis. ACIS parts can be generated and saved with Trelis, but in most cases are developed within a 3rd party CAD package and exported for use in Trelis. Trelis provides the capability to import ACIS solid models and make modifications to them so they can be meshed. Trelis incorporates the commercial ACIS libraries developed and maintained by Spatial Inc. for reading and writing ACIS format files. IGES and STEP format files can also be imported and exported to/from Trelis using the Spatial's libraries.

Import Options

It is possible to include free entities (vertices, curves and surfaces) in the file. The default operation is to read all entities in the file whether they are included as part of a body or are free. By using any of the options no_bodies, no_surfaces, no_curves, or no_vertices, the user may exclude certain types of free entities.

The group option of the import command will allow the user to create a group for each set of imported geometry. The newly created group can later be accessed using the name or id specified with the group option.

The import capability of ACIS files supports both the ASCII format (.sat) and binary format (.sab). When importing, the filename extension will determine the default file type, be it ASCII or binary. A (.sat) extension will default to ASCII, while a (.sab) extension will default to binary. If you use a different file extension you can specify the type with the [binary|ascii] option. Binary files can be significantly faster but are not guaranteed to be upward compatible, nor cross-platform compatible. Therefore, it is recommended that models be archived in ASCII format.

Normally the numerical IDs of the geometric entities contained in the ACIS model are used directly within Trelis. The sort option provides the capability to compress the IDs read from the ACIS file. The sort option does the same thing as the compress ids sort command, but combines it with the import command to remove a step in the process.

The show_each option is a graphics option that applies to how the volumes are shown as they are imported. If there are multiple volumes in the file, the graphics display will be updated between each volume during import.

The attributes_on option will enable attribute support for the file. Attributes include properties like entity color, entity id, and meshing scheme. Including the attributes option will only affect the current import. The settings will be restored to their previous settings after importing.

The separate_each option creates a separate body for each volume that is imported, preventing multi-volume bodies from being imported.

When importing, the use may specify the scope of the merge using merge_globally. The default behavior is to merge within the scope of the file being imported. With the merge_globally option, imported entities will merge with anything, including entities already in the Trelis session that have merge attributes on them.

Use the heal option to heal the entities when importing.

Importing ACIS files at startup

ACIS files can also be imported using the "-solid" option when starting Trelis from the UNIX command prompt. (See Execution Command Syntax for details.) Note that the filename must be enclosed in single or double quotes. This command will create as many bodies within Trelis as there are bodies in the input file.

See also Exporting ACIS Files.