Archive files are compressed files that contain all the numerous input files that make a model. The archive file can also include the results. Not only does the archive file use less disk space, but compressing the model to one file makes it easier to store the model or to transport it between different users. The format is similar to a zip file format and can be read with WinZip or Pkzip.
Archive files (.ach) can be accessed from 
Archive. This option has five choices to choose from: Create, Retrieve, Repair, Delete, and Manage Existing.
Create command
The create option will allow you to create a file with a .ach extension. When you select the Create command the Archive Creation Options dialog will appear:
You can choose between Model only and Model and results. Once you press the OK button, a compressed file with the .ach extension will be made. This makes it so only one file is needed to archive. This is a good way to back up a model. Also, it is very useful to keep a record of your model. The .ach file is the only file needed to open your model.
The Model only option will only include the loads, geometry, element data, material data, global data, and any other input data (.fem file and input stored under the modelname.ds_data folder.) Pre-meshed wireframes, previous versions, or result files are not included. The Model and results option will include every file in the current directory with the model name and all files under the modelname.ds_data folder. This will include pre-meshed wireframes, result files, log files, screen captures (if they were named the same as the model name), and meshing result files. Both options include all the design scenarios in the model.
The archive only includes files related directly to the current model. If any of the design scenarios access results from a different model (a file with a different name), those external results are not included in the archive. Therefore, the other model or models should be archived also.
The archive utility can handle approximately 2^64 number of files and 2^64 bytes per file, both of which are beyond realistic capabilities with current software and hardware.
If you are having an analysis-related problem that you need to send to Technical Support, archive the model with results. If the archive file is too large to send via e-mail, archive the model without results and attach the processor log files that will include the error messages so that we will know exactly where to focus on your model.
Retrieve command
If you select the Retrieve command, you can retrieve an existing archive file. This will let you unzip the archive file and display the model in Autodesk Simulation so that you can make changes to it. For example, you will need to use this option to retrieve the verification examples from the AVE Manual.
Manage Existing command
Use the Manage Existing command to see and manage an existing archive file. The dialog lists all the files in the archive file. Remove or update any file.
Repair command
If an archive file has become corrupt you can use the Repair command to fix it.
Delete command
The Delete command will bring up a dialog where you can select an archive file. The selected archive file will then be deleted.