If you are part of an engineering-design team with multiple people working in tandem, there's a good chance you've encountered unresolved links while working with associated CAD files. It's not uncommon to find that a co-worker or network administrator, for one reason or another, has renamed a directory or moved some files after you've left work. When you return the next day and begin to work, you realize the software can't find the files your design was referencing a day earlier. Now you have to spend time resolving your assemblies, which could take hours. This is time that you need to complete your project on schedule.

Unresolved files are typically the result of data being relocated. The problem often grows as users unknowingly overwrite or lose files. Project Files, an innovative tool in Autodesk Inventor software, provides the functionality that alleviates these troubles. In the first part of this two part series, I will explain the concepts behind Autodesk Inventor's Project Files: what they are, how they work, and how Project Files will fit into your environment, helping remove the pesky issue of unresolved links.

Project Files
Project Files are text files with a .IJP file extension that contain a list of paths to various folders. They break the dependency between your Autodesk Inventor dataset and its file locations. This basically means that your files may be relocated without editing assembly or drawing files. Guided by a Project File, Autodesk Inventor is able to find the data in the new location without the hassles associated with unresolved links. This is possible because Autodesk Inventor's documents only store a reference's file name, not its location. Instead, the software relies upon Project Files for these locations, meaning the software is flexible with data storage. As an assembly is opened, Autodesk Inventor will automatically search for the data it needs based on the locations listed in the active Project File.

How They Work
For many customers, Project Files provide sufficient design management enabling them to avoid using a PDM system altogether. To simplify project management, Autodesk Inventor lets you create a separate Project File for each design. This unique functionality changes the focus of the data you use on a project-by-project basis. When an assembly is opened, Autodesk Inventor uses search paths within the active Project File as a guide to locate component parts and sub-assemblies. There are four different types of search paths that can be defined within a Project File: workspace, local, workgroup, and library. These search paths make Project Files flexible, allowing Autodesk Inventor to pull data from various independent locations.

• Workspace. This is a "work-in-progress" location on your personal workstation and acts as the default location for creating new files. Only one workspace can be defined with each Project File.
  
  
• Local Search Path. Local search paths point to local and/or network locations that only you have access to. You might copy a released design to a local search path location in order to create revisions, modifications, or a one-off design. There can be several local search paths.
  
  
• Workgroup Search Path. This search path is defined for file locations that will be accessed by other people working on the project. This could be server space reserved for a project or the location where released files are stored. There can be several workgroup search paths.
  
  
• Library Search Paths. This is the location where you would find your company's standard parts, such as fasteners and other hardware. These search paths often point to a server, and parts stored in this location rarely change. There can be several library search paths.

Autodesk Inventor's Project Files provide flexibility in defining where files are stored. To components in an assembly, the software follows the search paths in a specific order until it finds the file. First, Autodesk Inventor looks for files by following the library search paths, which as you may recall, are commonly used to store standard and purchased parts. Since standard hardware and purchased parts can represent a significant number of the total components found in an assembly, you can decrease the amount of searching Autodesk Inventor must do to resolve those components by placing them in the library search path. This equates to quicker load times. This also helps simplify the management of the libraries since common parts can be located in one directory on the server.

In order to find a library part, Autodesk Inventor looks for a library designator defining the location for the part in the assembly file. Library designators are labels Autodesk Inventor internally stamps on library parts. They are noted with "%xxxx%." If Autodesk Inventor finds a library designator, it looks in the appropriate library listed in the Project File; otherwise, it searches the workspace, local paths, and workgroups.

Figure 1. When opening an assembly, Autodesk Inventor searches for referenced parts in user-defined locations that are identified by the active Project File. The Project File removes the dependency between the data set and the file locations, helping to eliminate problems commonly encountered when relocating data. Here you see the sequence Autodesk Inventor follows to resolve an assembly.