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ACIS saves, or stores, model geometry information to
ACIS save files (also known as SAT, part save files, or part files).
ACIS also restores model information from these files. These files have an open format. Geometric entities are saved in the form of an entity list.
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ACIS provides the API functions
api_save_entity_list and
api_restore_entity_list for saving models to and retrieving models from a disk file. Two additional API functions,
api_save_entity_list_file and
api_restore_entity_list_file, allow models to be saved and restored to media other than a stream file.
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Applications use these functions in many ways. Single or multiple
ENTITYs can be saved in a file, and applications can intermix their own data with
ENTITY_LIST data. For testing or debugging purposes, it is possible to edit a file and remove all but the data of interest and load the file into a test or demonstration application, such as
Scheme AIDE.
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There are two types of
ACIS save files: Standard
ACIS Text (file extension .sat) and Standard
ACIS Binary (file extension .sab). The only difference between these files is that the data is stored as ASCII text in a .sat file and in binary form in a .sab file. The organization of a .sat file and a .sab file is identical; the term SAT file is generally used to refer to both types.
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Text file saves have the advantages of being human-readable and being portable between different platforms. Binary saves are not human-readable and may not be portable across platforms, but writing records in binary is roughly twice as fast as writing in text and the files are significantly smaller. Write and read binary files only by the same version running on the same type of hardware.
ACIS can read and write any format of binary file on any platform. The selection of binary file format to be written is controlled by the
binary_format option. The default format for writing a binary file is the native format of the machine on which it is being written.
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Two sets of information may be available at any one time. There should always be information about what is going to be saved. That is stored in a
FileInfo object and queried with the
env:save-product-id/units Scheme extension. If one has recently retrieved a file, there should also be information about that file. It is stored in a
FileInfo object and queried with the
env:restored-product-id/units Scheme extension. Of course, both of these can be accessed through
C++ by obtaining and querying the appropriate
FileInfo object in the kernel context object.
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Beginning with
ACIS Release 6.3, it is
required that the product ID and units be populated for the file header (using class
FileInfo) before you can save a SAT file. Refer to the reference templates for class
FileInfo and
function api_set_file_info for more information.
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