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Autodesk Inventor: Content Style Guide By Neil Munro Most new Autodesk Inventor® users implement the software by integrating with or replacing an existing CAD application. Most companies have an extensive base of common components and designs that are reused as is or as the foundation for subsequent designs. Regardless of the CAD system, component libraries and reuse of existing data are crucial for efficient design. This style guide discusses tools and techniques for generating and managing these common components in Autodesk Inventor software. Autodesk Inventor Files Understanding how Autodesk Inventor stores data is fundamental to managing universal and project-specific components. At the file level, each part and assembly is stored as a separate file when saved to disk. An assembly file has references to the required part and subassembly files and also contains information on the position of each component and the relationships between components. Figure 1 shows an assembly model and the assembly browser.
Drawings are also separate documents. The software generates drawing views from referenced models. Given this individual file approach, it is important to have file management strategies in place before you begin your first project with Autodesk Inventor software. An in-depth discussion of Autodesk Inventor file management is beyond the scope of this guide, but general strategies are discussed throughout. Subassemblies It is good modeling practice to create a logical structure of subassemblies to build larger assemblies. This structure typically follows the manufacturing process of the product, in which subassemblies are created and then combined to form the top-level assembly. The default behavior of a subassembly is to act as a single component in the parent assembly. Only a few assembly constraints (position and orientation relationships between components) are required to position the complete subassembly. Because you don't need the parent assembly to evaluate the constraints between components in the subassembly, the assembly is more responsive during constraint placement. Logical subassemblies can also reduce file management issues and promote component reuse. Since common components are incorporated into most subassemblies, a well-planned strategy for creating, storing, and finding these components is key to efficient assembly design.
Modeling Strategies for Standard Components So, what does this mean to you in the context of creating standard components? The key to generating efficient standard components is to create the simplest model that will do the job. This strategy applies not only to standard components but also to all levels of the design, from individual parts to the top-level assembly. Many Autodesk Inventor users actually use the word fun in the same sentence as modeling parts and assemblies. Adding features can make the model look more realistic but can significantly degrade performance (see Figure 4). For example, 300 socket head cap screws with modeled serrations on the head and 0.1 mm fillets on every edge can slow view manipulation and assembly editing.
The degree of detail required in a model can vary widely. Some questions you might ask to determine the level of detail required are as follows:
Images can also be accurately placed and sized in a specific part feature to represent a decal or replace geometry that would be costly to model, as shown in Figure 6.
Model Sources and Formats When planning a model, ask this question first: Do I need to model this, or is it already available somewhere else? Vendors are increasingly likely to have 3D models of their products available in a file format that you can open in Autodesk Inventor. Several user websites dedicated to Autodesk Inventor software are good sources for standard components. In addition, Autodesk Inventor ships with a content library containing a wide range of parts in 19 different standards (ANSI, ISO, and so on). If you can't find what you need, you can always build the model yourself. iParts The Autodesk Inventor community is a good source for models of standard components. Several websites have user-generated Autodesk Inventor models. These models may be in standard part or assembly format, but families of related parts, such as fasteners or fittings that vary in size, are often available as Autodesk Inventor iPart factories. You can also create your own iPart factories from Autodesk Inventor part documents. An iPart factory is a single part file that includes a table outlining the possible variations in the part. When you select an iPart factory for placement in an assembly, you see a series of key options that enable you to fully define which variation of the part you want to place. An iPart child matching your selections is generated (or reused if previously generated) and placed as a part occurrence in the assembly. Following is a step-by-step overview of generating an iPart factory for a dowel and then placing one of the variations (iPart child).
1. Create a model containing all features that may be included in any of the iPart children. Features that appear in some versions of the part can be suppressed in other versions. Resist the temptation to add fine details. Model only the features required for your specific circumstances (see Figure 10). 2. Rename the part parameters (sketch dimensions, extrusion lengths, and so on) that you will manipulate to create the different iPart children (see Figure 11).
3. Start the iPart Author tool. Renamed model parameters and any user parameters are automatically added as parameters that can vary between iPart children (see Figure 12). The current values of these parameters define the single version initially available.
4. Add items from the other tabs as required:
5. Select critical parameters as keys for the iPart, as shown in Figure 14. Key values are presented during iPart placement to provide a hierarchical selection of the iPart child. In this example, the diameter and length of the dowel are the only selections required to fully define the dowel. Diameter is set as the primary key, and length as the second key. When placing the dowel in an assembly, you first select diameter, thus limiting the length selection to those iPart children matching the selected diameter. 6. Add rows to define each iPart child. You can edit the table in Microsoft® Excel to speed up row additions and create relationships between table cells. In Figure 15, the 5/16" diameter dowels have the Chamfer2 feature suppressed.
7. Save the iPart factory to a folder specified as a library search path. See "Managing Standard Components" at the end of this document for more information on project files and search paths. 8. To place a version of the iPart in an assembly, you select the iPart factory from the Open dialog box during component placement. A dialog box presents the iPart keys, so you can place the desired iPart child with only a few selections (see Figure 16). The software generates the selected iPart child (or reuses it if it already exists) and places an occurrence in the assembly. Each child placed in the assembly contains the iPart table, so you can replace the occurrence with another iPart child simply by selecting new keys in the table.
Reusing Existing Data Some or all of your company-specific standard components may already exist in DWG or other formats. Several options are available for bringing these components into the Autodesk Inventor software application. The Autodesk Inventor DWG File Import wizard makes it easy to import 2D geometry and 3D solids from AutoCAD® drawings (see Figure 17).
You can easily import an AutoCAD solid as a base solid in Autodesk Inventor. A base solid does not contain feature information and so cannot be used as an iPart factory. If the imported solid contains unimportant details such as fillets and chamfers, you can use the base solid editing tools to permanently remove these features, as shown in Figure 18.
Drawing files with multiple 3D solids are imported as an Autodesk Inventor assembly with a separate part file generated for each 3D solid. Autodesk Inventor software cannot import AutoCAD surfaces or 3D wireframe geometry. A more common consideration is how to reuse existing 2D AutoCAD data. Carefully consider how the component will be used before deciding on a course of action.
In addition to native Autodesk Inventor models, you can open .sat, .stp, .iges, and Pro/ENGINEER® part and assembly models (V20 and earlier). When you open a 3D solid model saved in a nonnative format, the resulting Autodesk Inventor model is a single base feature similar to an AutoCAD solid (see Figure 19). IGES files usually contain surface information rather than solids. Autodesk Inventor software imports IGES surface files into a construction environment where you can stitch the surfaces together to form a closed boundary and then promote this to a solid model. These single-body solids are usually sufficient since the intention is to use the model as a standard component that will not be modified. When saved, imported components are stored as native Autodesk Inventor files.
Autodesk
Inventor Content Library
As with iPart factories, the software generates a selected component the first time you place it in an assembly. Standard library parts include appropriate iMates (see the iMates section of this guide for more information) attached to the geometry typically referenced when assembling the part. In addition, you can easily replace one or all occurrences of a library component with a different version. Components are placed from the library catalog using Autodesk's i-drop® technology. Once the size parameters of the part have been specified in the library browser, you click in the component image window to fill the i-drop symbol and then drag to the Autodesk Inventor graphics window to place an occurrence in the assembly (see Figure 21).
With i-drop technology you can drag content from other servers, including web-based servers, directly into your assemblies. Tools to add to existing libraries or create your own i-drop-based content libraries are not yet available. You must create iPart factories or use other methods for components that are not included in the supplied content library. The content library also includes custom library parts, currently limited to common steel shapes such as channels, flanged beams, and angles. As with custom iParts, you specify the length of the custom library part during placement and provide a file name and location to store the custom part. Unlike standard library parts, custom library parts are editable and you can add features after placement (see Figure 22).
Model
Creation Summary iMates
You can combine individual iMates to form a composite iMate. As with single iMates, you can elect to search for matching composite iMates when placing a component, or you can press Alt and drag the symbol to connect matching composite iMates after component placement. Regardless of the methods you use to create standard parts, consider adding iMates to all your standard components. All standard parts in the content library include appropriate iMates, iParts can include iMates, and standard parts and subassemblies can also contain iMate definitions. Component Metadata
You can extract these properties in assembly bills of materials and in drawing parts lists and title blocks (see Figure 26).
Standard parts, including iParts and parts placed from the content library, all contain the same set of standard iProperties. You can include any iProperty in an iPart factory. iProperty values can be changed for each row (iPart child) in the table. To use iPart properties in assembly bills of materials and drawing parts lists, you must include them in the iPart factory definition. Standard and custom parts placed from the Autodesk Inventor content library have predefined values for some iProperties. You can edit the iProperty values of a library part only after placing it in an assembly. You can use iProperty values to filter and group components in an assembly. For example, you can improve performance in large assemblies by turning off the visibility of noncritical components such as fasteners and other standard components. In an assembly with hundreds or even thousands of standard components, manual selection of these components is impractical. You can search for and select components in an assembly using the Find tool. You can base the search on any number of rules, including iProperty values, as shown in Figure 27.
The Keywords iProperty on the Summary tab (see Figure 28) is a good candidate to use as a Find tool filter. Consider adding one or more keywords to your standard components that can be used to group similar components. You can use the Find tool to quickly select all components containing one or more keywords. You can then hide this group of components. Finally, you can save the current state of an assembly (component visibility, colors, and so on) in a design view that can be recalled at any time (see Figure 29).
Managing Standard Components Although it's the last topic in this guide, library management planning should be in place before you create standard content libraries. The key to managing Autodesk Inventor files is a thorough understanding of project files. A complete discussion of project files is beyond the scope of this guide, but important concepts and details on libraries and library search paths are discussed here. For more information on project files and Autodesk Inventor file management strategies, see the Autodesk Inventor File Management document included on the installation CD. Project Files and Library Search Paths A project file contains search paths that reference storage locations that are searched to find referenced files during file opening. An assembly file holds references to all the first-level subassemblies and parts that constitute the assembly but does not use hard-coded paths to find these files when the assembly is opened. Instead, search path information in the active project file is combined with the referenced file name and any subfolder information to provide a file search location. Search paths are grouped for specific purposes, but all include a search path name and the search path. The search path location can be a folder on a local drive or server (see Figure 30).
Standard components are, by definition, parts and subassemblies that are completely defined and do not change from project to project. Library search paths in a project file have specific properties designed to support standard component libraries. When a component is loaded from a folder specified as a library search path, the assembly stores the following information:
The search path name storage is unique to library search paths. As a result, the assembly can restrict its search for a library component to the one library search path folder and the subfolder location, if included. This short list of search locations reduces the time to resolve file locations and speeds file opening, especially with larger assemblies. This search path name reference requires that the library search path name remain fixed. A second advantage of referencing a storage location with a library search path is that a file loaded from a library search path folder is read-only and cannot be edited. You can protect files from inadvertent change by locating them in a folder that is referenced by a library search path. Libraries are often stored on one or more servers and made available for all design groups or members. You can also have project-based libraries that provide specific components for a design. You should create a common project file that includes the common library (and other) search paths for a design team. This project file is then merged into individual project files to ensure that all team members have access to the same libraries. Autodesk Inventor content library parts, iParts, and existing models can all be stored in library search path locations. Content Library Setup
1. Select the Library pane in the assembly browser (see Figure 31). 2. Click the Configure tool at the bottom of the browser. 3. In the Configure Servers dialog box, select a server from the list (the Autodesk Inventor content library is stored on a single server), and click Edit. 4. In the Configure Server Local dialog box, select Parent Assembly or a search path from the Storage Location list (see Figure 32).
iPart Factories and iPart Children Project file search paths control storage locations for both iPart factories and children. In a standard iPart factory, all variations of the part are defined in the iPart table and generated iPart children are saved automatically. Factories are typically used by all design team members and made available on a common server. To take advantage of the editing restrictions of parts in library search paths, you should include the iPart factory folder as a library search path. To provide even more protection, you can also set read-only file permissions on iPart factory folders. You can store all iPart factory parts in a single folder (Figure 33) or distribute them in folders below a top-level folder (Figure 34).
With the search path(s) in place for the iPart factories, you then add corresponding (proxy) search path(s) for generated iPart children (see Figure 35). The iPart child search path name must match the name of the corresponding iPart factory search path, with the addition of a leading underscore. The storage location is arbitrary but is often on the same server. Users must have write permission to the iPart children folders. For multiple iPart factories provide a parallel set of folders to hold similar components. Figure 36 shows a typical setup for multiple iPart factories.
When you generate the first instance of an iPart, a new folder is added below the iPart child folder. All variations of the iPart are saved to this folder. For example, you have one iPart factory part in the \\server 1\common\iParts folder: \\server 1\common\iParts\Strap.ipt When you create the first Strap iPart child, the software generates a folder below the corresponding iPart proxy path. The folder name matches the iPart factory part name. The iPart child is saved to this folder using the file name defined in the iPart factory. \\server 1\libraries\iParts\Strap\Strap-M30xM65.ipt If the iPart children are specific to a project, you can specify a local folder for the proxy path.
Changes to an iPart factory after iPart children have been generated can require additional work to ensure that all occurrences of the iPart are updated. Do not make iPart factories available until the design is complete. Adding variations of the part (table rows) is acceptable, but changing the structure of the iPart factory (adding table columns and changing keys) may require that you reselect the iPart variation in existing assemblies. Custom iPart factories do not require corresponding proxy paths since you are prompted for a part name and location for each iPart generated from the factory. The storage location must be a search path (or subfolder of a search path) in the active project file. Standard Component Resources Many manufacturers provide 3D models at their sites: https://www.mymcad.com/KWiK/Mcad.htm https://www.partspec.com https://www.cadalog.com |
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