Managing Large Assemblies with Autodesk Inventor

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1 11/29/2006-5:00 pm - 6:30 pm Room:Marcello (MSD Campus) Managing Large Assemblies with Autodesk Inventor Peter Maxfield - Autodesk, Inc. MA25-5 In this class, we ll look at the effective use of Inventor R11 functionality to design, model, and document large assemblies. We ll discuss all of the new large assembly management tools available to you in R11. We ll also discuss best practices for managing large assembly models. About the Speaker: Peter has been with Autodesk, Inc. for four years as a product designer. During that time, he has worked primarily on the Assembly environment of Inventor. He has also helped develop other functional areas of the software, such as Routed Systems, Vault, Frame Generator and, most recently, dynamic simulation and stress analysis. Previously, Peter worked as a mechanical engineer for Praxis, a consumer product design firm, as well as a product designer at PTC. He earned his BS degree in Mechanical Engineering at Cornell University. Stay Connect to AU all year at

3 Introduction Autodesk Inventor users are designing everything from wristwatches to full-scale manufacturing facilities. Some projects require precision at the level of a human hair, while others rely on two story tall jigs to weld components together. What is common among these users? They all require effective management of computer memory, while demanding optimal performance. Release 11 of Inventor provides new tools to ensure your session is as streamlined and efficient as possible. Making use of a new technology, component suppression, data can be loaded and unloaded as needed. In keeping with the Inventor tradition of making tools as approachable as possible, experienced users are able to jump right in and realize gains immediately, based on familiar paradigms and workflows. By the end of this course, you will have exposure to the full suite of this new technology (the same in both AIS and AIP), ready to use on your own production data. Please note, some guidelines in this handout may be date dependent. All hardware recommendations are based on common standards as of November, Terminology To start, here are some common terms that we will use throughout this session: Capacity: This is a general term indicating memory consumption. OS settings will vary the amount provided to Inventor (2GB vs. 3GB vs 4GB). Representation: An assembly-owned object, capturing a set of modifications to various attributes within the assembly. They come in three flavors: Design View Representations handle component visibility, color, enable state, browser expansion, and camera angle. Positional Representations can modify constraint values, suppression, component offsets, and flexible status. New to R11, Level of Detail Representations modify component suppression states. All representations can be nested, meaning a parent assembly Rep can call upon a subassembly Rep (of the same flavor). This allows the subassembly to govern its own attributes. The three representations can be used together as best needed for a given task. Master rep: The base representation (one per flavor). An assembly always maintains a master state, from which the Reps make modifications. Configuration: Also known as iassemblies, configurations provide a table-driven method of designing a product family. If you are familiar with iparts, you will become easily familiar with iassemblies. R11 has several enhancements to both types of table-driven components to make them more reliable, and faster to publish. Component or Document or File: A single part, assembly, weldment, or sheetmetal object. Occurrence: When a component is used in multiple locations within an assembly, each one is called an occurrence. Often, different occurrences may have unique attributes, such as color, which is governed by a parent assembly. The path to an occurrence is called deep if the path is more than one generation long. Edit Target: In Inventor, the user can modify many documents with one action. At any given time, however, one document will be the primary edit target, either as the active window, or based on an edit-in-place workflow. Capacity Meter: A new indicator in R11, found in the status bar to the right of the application. Provides information on number of occurrences (or total tree nodes) in the Edit Target, number of Files open in session, and a meter gauging the amount of memory consumed which is available to Inventor. 2

Common Questions When should I use Level of Detail Representations? A common question with regards to LODs is Why use them when I already have Visibility?

4 Common Questions When should I use Level of Detail Representations? A common question with regards to LODs is Why use them when I already have Visibility? The answer to this lies in what happens behind the scenes. When turning the visibility off for a component, all of the geometric and design data for that component remains loaded in memory. While the screen will have fewer objects displayed (which can be a benefit to graphics performance), the system will continue to behave as before. When a component is suppressed, it is removed from memory. References to the component are put to sleep, and will reawaken when the component is unsuppressed. In this manner, the user is able to take control over how much data is being consumed at any time. It also allows working on assemblies much larger than ever before- by some measures one or two orders of magnitude! Will suppressing components limit Inventors capabilities? We designed the component suppression technology to be as agile as possible. Many features will continue to function as normal, even when components are suppressed. For instance, the Mate, Align, Insert, and Tangent constraints will maintain a lightweight cache of geometric information, allowing them to perform as normal, even when referenced components are suppressed. Figure 1: The Engine from the Samples set, first with all components loaded, then with the connecting rod suppressed. Note the engine continues to function, with proper kinematic motion. The rod s bounding box is shown due to the browser entry being selected. Other functions that will behave with full fidelity include the Mass Properties update, BOM report, Parts List, Weld bead update, and assembly feature update. In all cases, suppression states will be respected, maintaining memory consumption as low as possible. At times, the system may load a small amount of data from a suppressed component, but every attempt is made to return to the same memory state as when the command was started. DWF publishing is one exception, by design. If a component is suppressed, it will not be present in a DWF export of the assembly. Working in a Team Inventor supplies three system LODs (All Components-, All Parts-, and All Content Center Suppressed), which will exist for any assembly and weldment. It may help to establish some standard LOD names to use in a team, such as Simple, No Routed, or the like, to encourage a consistent set of reliable, lower-weight LODs. You could even put these into your template, to be sure each new assembly has them already created. 3

5 How do I use the Capacity Meter? The new indicators in the lower right of the application are meant to help the user work proactively. No matter how good the hardware, memory limits are going to be met, at times. The green/yellow/red gauge is the most crucial item to keep an eye on. After Inventor is first loaded, this meter is zeroed out, thus displaying the remaining memory available for data. If you hover the mouse cursor over the gauge, a tooltip will indicate the consumed and free memory remaining (MB). Note, as different aspects of the system are loaded (drawing environment, routed systems, etc), small portions of this memory will be used to handle their functionality. They will not be unloaded automatically, but not to worry; if they are not in use, this memory will be reused. The middle number is the number of open files in session. This is the next most applicable indicator of memory consumption. Granted, different models have different complexities, so be cautious when comparing one dataset to another based on this number. Finally, the number to the far left is an occurrence count of the edit target. This counts each and every node in the assembly tree. This number is provided more as evidence of graphic performance expectations, and not so much memory impact. In the case of drawings, it is a sum of all occurrences across all views on all sheets. Thus, at times, this number could become quite large. However, by taking advantage of LODs, items such as Parts Lists will remain fully accurate, without loading much data at all. How can I build effective LODs? There are a variety of methods to creating LODs, each with benefits for specific tasks. If you have experience with Design Views, you are already familiar with their basic use. In the drill down method, start with the Master LOD, and suppress components that are not of use. In this manner, you can be sure that all components are loaded, except those that you are confident are not needed. Conversely, it may be best to start with a system LOD such as All Parts Suppressed, and unsuppress components that are of interest for a given task. With extremely large assemblies, this is the most efficient way to build up a LOD rep. Regardless of the method, be sure to take advantage of the Selection Tools and the Find command. Experiment with them all; they can be very handy! For instance, if you need to make a basic bounding layout drawing of an assembly, all of the internal components will not show up at all. The Internal Component tool can help find these components, allowing them to be suppressed in one action. Save this to an LOD, and the drawing view will never have to conduct the hidden line calculations on these components. Most often, it will help to use the Part Priority when using the Selection tools. Using Component Priority will restrict the selections to only work with the first-level children, which may not be granular enough for selections based on zones or size. Figure 2: Selection tools 4

6 Associativity Take advantage of the nesting abilities of Representations. By managing Rep states within subassemblies, every consumer (parent assemblies, drawings, presentations, etc) can take advantage of these settings. This eliminates duplicate efforts, and means edits to the Reps in the subassemblies will be witnessed in the consumers. iassemblies can also be nested. The member of a subassembly iassembly can be selected with a Table Replace column. Figure 3: Top level LOD references LODs from children subassemblies. Drawing Environment There are several enhancements to the Drawing environment, beyond the ability to use LODs when making Views and Parts Lists. Within the Application Options, Preview adjusts the depth of information shown during initial View placement. Note, Partial Preview will show only the largest two-thirds of the components, by size, with a maximum of half the components hidden. The Section Preview as Uncut option will significantly enhance the preview performance when making a section view. Lastly, the Memory Saving Mode option will cause the environment to trade performance for memory optimization. View calculations are done in a serial fashion, loading components in stages and then unloading them. Routed Systems Components from Tube & Pipe and Cable & Harness assemblies can be suppressed like any other component. This can be very helpful when working on other systems that are not impacted by the routed system components, avoiding update overhead and the potential graphical lag. Conversely, component suppression can help make an assembly more manageable when it comes to routing, say, an electrical umbilical down the length of a large design. Such a workflow may demand a single Cable & Harness assembly, but given the number of systems with which the cable may interact, using LODs effectively can be a huge time saver. Migration In order to take advantage of LODs, the assemblies must be migrated to R11. It is recommended to use the Task Scheduler to conduct these migrations. This will guarantee an efficient, bottom-up approach, and generate a log file to assist with tracking down any errors encountered. 5

7 Hardware Best Practices The immediate year will see some astounding shifts in the capabilities of the common workstation. Already, multi-core processors are becoming the norm, x64 is defacto in most desktops, and Vista is just around the corner. A 500 GB hard drive is becoming affordable, as is dual 20 inch LCD monitors with 256 Mb graphic cards. It s a great time to be a CAD user. That said, the following recommendations should be interpreted with an eye on the abilities of the hardware in use. It is always good practice to keep your system optimized, backed up, and defragmented on a regular basis. RAM Possibly the best investment in hardware is RAM. Avoiding page swapping can lead to tremendous savings in performance, and generally provide more breathing room for not just Inventor, but all applications that are required day to day. 32-bit Windows applications are restricted to 2GB of memory access. As of Inventor R6 SP2, the 3GB switch can be used to provide 3GB to all applications. Note, this reduces the space available for the OS to 1 GB, so it is recommended to only set this switch when absolutely necessary. In order to enable the feature, you must change your boot.ini file (which is typically located at C:\boot.ini) to have the /3GB option, as shown below. It is recommended that you copy the original line, modify the copied line to add the option and the identifying string. This will enable you to choose at boot time whether to use the option or not. The default will be to use whichever line is first. ***WARNING*** Problems caused by improperly editing the BOOT.INI may prevent your system from booting correctly and could render your computer operating system unusable. Please consult the Microsoft Knowledge Base for more information at This feature only works on Windows XP sp2. It is not possible to enable the feature on Windows NT, Windows 2000, or Windows 9x. Edit the BOOT.INI file only at your own risk and only after backing up the original. Example BOOT.INI file: [boot loader] timeout=30 default=multi(0)disk(0)rdisk(0)partition(2)\windows [operating systems] multi(0)disk(0)rdisk(0)partition(2)\windows="microsoft Windows XP Professional" /fastdetect multi(0)disk(0)rdisk(0)partition(2)\windows="microsoft Windows XP Professional 3GB" /3GB /fastdetect You should insure that you have a total of at least 3GB set aside for the Paging File Size to fully utilize the available address space. Also note that every concurrently running application is sharing the available paging file size, so setting to something more than 3 GB (such as 4 GB) is recommended. 6

General Points on Pagefiles Minimize Pagefile Fragmentation. Always create the pagefile on a freshly formatted empty partition, ensuring fragmentation is minimized.

8 General Points on Pagefiles Minimize Pagefile Fragmentation. Always create the pagefile on a freshly formatted empty partition, ensuring fragmentation is minimized. Min & Max Setting Set both the minimum and maximum value for the pagefile size to the same max value. This ensures the whole amount of disk space is allocated in one go, minimizing fragmentation of the disk. It also guarantees memory allocation is not slowed down by resizing virtual memory. Pagefile size If only Inventor is installed and work is with (very) large assemblies, set the pagefile size to 2.25GB. If the machine is used for other resource intensive applications such as Mechanical Desktop (i.e. during a translation of a dataset from MDT to Inventor), only then consider changing the pagefile size to 4GB (maximum amount of memory Windows can use) Ratio of Virtual to Physical Memory Keep in mind that if the amount of virtual memory compared to the amount of physical memory gets disproportionate (5:1), performance will suffer as the machine will perpetually reading and writing to disk. Multiple Pagefiles If using more than a single pagefile, do not place them on different partitions of the same physical disk drive. Do place them, however, on the fastest physical drives you have. System Files Avoid having a pagefile on the same drive as the system files. Fault-Tolerance Avoid putting a pagefile on a fault-tolerant drive, such as a mirrored volume or a RAID5 volume. Pagefiles do not need fault-tolerance, and some fault-tolerant systems suffer from slow data writes because they write data to multiple locations. 7

9 64 Bit Solutions As stated earlier, there are many changes afoot with workstation configurations. The best advice at this time is to invest in RAM and an x64 based system. These can run an x32 OS just fine, while being upgradeable to whatever flavor of OS you choose in the near future. This does not mean current 32 bit machines are obsolete; quite the contrary. With at least 1 GB of memory, a 32 bit machine will be able to run the Inventor suite of products quite effectively. This table illustrates some differences between the system capabilities: General Memory Limits 32-Bit 64-Bit Total virtual address space (based on a single process) Virtual address space per 32-bit process Virtual address space per 64-bit process 4 GB 16 TB 2 GB (3 GB if system is booted with /3GB switch) n/a 4 GB if compiled with /LARGEADDRESSAWARE (2 GB otherwise) 8 TB Paged pool 470 MB 128 GB Non-paged pool 256 MB 128 GB System Page Table Entry (PTE) 660 MB to 900 MB 128 GB Physical Memory and CPU Limits 32-Bit 64-Bit Windows XP Professional 4 GB / 1 to 2 CPUs 128 GB / 1 to 2 CPUs Windows Server 2003, Standard Edition Windows Server 2003, Enterprise Edition Windows Server 2003, Datacenter Edition 4 GB / 1 to 4 CPUs 32 GB / 1 to 4 CPUs 64 GB / 1 to 8 CPUs 1 TB / 1 to 8 CPUs 64 GB / 8 to 32 CPUs 1 TB / 8 to 64 CPUs Note: An important consideration in the short term is that even 32-bit applications will benefit from increased virtual memory address space when running in Windows x64 Editions. Applications that are compiled with /LARGEADDRESSAWARE, as would be required to take advantage of the /3GB switch in 32-bit Windows, will automatically be able to address 4 GB of virtual memory without any boot time switches or changes to x64 Windows. Plus, of course, the operating system does not have to share that 4 GB of space, so it is not constrained at all. Note: The current x64 Editions of Windows actually only use 40 bits for addressing memory, yielding an address space of 240, or 16 TB. The theoretical maximum of a full 64-bit address space is 264 bits, equivalent to 16 exabytes (1.6x10 19 ). 8

Course Title: Assembly Tips and Techniques in Autodesk Inventor

Las Vegas, Nevada, December 3 6, 2002 Speaker Name: Neil Munro Course Title: Assembly Tips and Techniques in Autodesk Inventor Course ID: MA41-2 Course Outline: Investigate bottom-up, top-down, and middle-out