There are many reasons for performance issues on a CAD system. You can resolve some of them by upgrading to a faster computer or adding more RAM. Keep the CAD system “tuned up” by performing regular maintenance, such as defragmenting the hard drive, also resolves performance issues.
This section covers hardware requirements, best practices, and techniques to use when you have reached a performance impasse. The following information is a guide to areas you can fine-tune to have a positive impact on performance. You can employ only a few of the tips provided to improve performance!
There are options you can configure in Autodesk Inventor LT that strictly go to improving performance. For example, if you open a drawing file with Defer Updates enabled, you increase performance, but you do not change what Autodesk Inventor LT loads into memory.
Capacity refers to how much memory is required to do an operation combined with how much memory is being used by your computer at any single moment.
Note on 32-bit operating systems: Microsoft Windows has a limit of 4 GB of memory for every process or application such as Autodesk Inventor LT. By default, Windows reserves 2 GB of that space for the operating system, thus leaving 2 GB for tasks performed by applications.
If you routinely work with large data sets or can resolve performance issues by adding more RAM, consider upgrading to a 64-bit computer which can access terabytes of RAM.
2 GB of memory is not enough for users who commonly work on extremely large files and consume the full 2 GB of virtual memory space. It is important to keep this concept in mind when working with large files, and to determine whether the 3 GB switch feature is an option your computer may benefit from. By changing a few system files, you change the default, so that 1 GB of memory is used by the operating system and 3 GB are available to applications.
The following table compares the memory capacity of a 32-bit system with a 64-bit system.
|General Memory Limits||32-Bit||64-Bit|
|Total virtual address space (based on a single process)||4 GB||16 Terabytes|
|Virtual address space per 64-bit process||N/A||8 Terabytes|
|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|
Microsoft Windows reserves the upper half of the 4 GB virtual address space of any process for the operating system, and leaves the remaining 2 GB for the application process, including the space for the code pages, the stack, and all dynamically allocated memory.
Thus, Microsoft Windows operating systems support no more than 2 GB of memory usage for one application. The 3 GB feature divides the memory space differently, providing 3 GB for the application and 1 GB for the operating system. This is not a network server limit, but is relevant to users working with large, memory-intensive data sets.
To set the page file size, right-click My Computer Properties Advanced Tab Performance Settings Advanced Tab click Change in the virtual memory section. Enter 4096 in Initial size box as well as in Maximum size box and click on Set. Click OK.
To enable the feature
You must change your boot.ini file (which is typically located at C:\boot.ini) to have the 3 GB option, as shown below. It is recommended that you copy the original line, and then modify the copied line to add the option and the identifying string. This sets it up so you can choose at start time whether to use the option or not.
The copied line is show in green (last line), with the modified portions of the line shown in red.
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
To ensure this is working
To insure that Autodesk Inventor LT is actually allocating memory in the 3 GB range, start Autodesk Inventor LT. Click Help About Autodesk Inventor LT. The first line of text under the splash screen image should say: "Autodesk Inventor LT [release number] - 3GB" If the - 3GB is shown, Autodesk Inventor LT is successfully using the feature.
Each executable must be specially built to enable the larger address space. Only the Autodesk Inventor LT.exe has been enabled. Other executables shipped with Autodesk Inventor LT have not been enabled. Most likely, the applications provided by other software vendors have not been enabled to use this feature.
The feature only works on Windows XP. Furthermore, the Windows XP SP1 service pack disabled it. To re-enable it for Windows XP SP1, there is a hot fix from Microsoft that must be applied. To apply that hot fix (q328269_WXP_SP2_x86_ENU.exe), follow the instructions in the hotfix.txt file in the associated zip file. It is not possible to enable the feature on Windows NT, Windows 2000, or Windows 9x.
You may find that by using some of the other techniques described previously, you eliminate performance issues. If not, the next section offers suggestions for adjusting the Application Options to consume the least amount of resources.
The following settings on the tabs listed below can affect performance and/or capacity:
Show command prompting = Off
Undo: Make sure there is enough free space on the specified partition to accommodate the size of the undo file.
Background = 1 Color
Shadow options can effect performance for hardware supporting feature level 3.1 and lower. To find out which feature level your graphics card supports:
Turning off shadow effects will improve performance for lower feature levels. It is recommended that you experiment with one level at a time, in the following order, to find the right level of shadow usage.
Ambient Shadows = Off
Object Shadows = Off
Ground Shadows = Off
Other options for improving graphics response are:
View transition time = 0 Inventor manages view transitions automatically, however, you can override the automatic setting by reducing view transition time.
Minimum frame rate = 10 This option displays less graphical information during Pan, Zoom, and Rotate. This is automatically managed, however, the setting is there for you to manually override the automatic feature.
Use Direct3D graphics hardware
Be aware that memory consumption varies with different graphic cards. Review recommended video cards and other hardware components on Autodesk's Web site.
Use the default settings on this tab. If you experience stability issues, work your way down the list of available options on this page.
To improve performance and capacity:
Leave the Autoproject edges for sketch creation and edit option not selected to improve performance and not sacrifice capacity when not needed
Leave Note Icons not selected to increase capacity.
Inventor offers simple, easy to use visualization effects to enable realistic looking models in the viewport. The effects available depend on the capabilities of your graphics hardware, operating system, and the Inventor graphics hardware setting in the Application Options > Hardware tab.
The following illustrates the visual effects you can experience at the various Autodesk Feature Levels, and the table below specifies the minimum system requirements for each level.
|Graphics HW Setting|
|Autodesk Feature Level||Advanced 4_1||Full 3_1||Medium 3_0||Basic 2_0||Legacy|
|Windows OS||Windows 7, Vista SP1 or later||Windows XP SP3 or later||Windows XP SP3 or later||Windows XP SP3 or later||Windows XP SP3 or later|
|Graphics Capability||DirectX 10.1 Shader Model 4.0|
Shader Model 3.1
Shader Model 3.0
Shader Model 2.0
Fixed function pipeline
|Graphics HW Memory||512 MB (1 GB recommended)||512 MB||512 MB||256 MB||128 MB|
|Graphics HW Generation||2008 or later||2005 or later||2005 or later||2003 or later||1998 or later|
You can query your system to find your Autodesk Feature Level in two different ways:
The following table indicates which visual effects are supported by each of the Autodesk feature levels.
|Visual Effect||Advanced 4_1||Full 3_1||Medium 3_0||Basic 2_0||Legacy|
|Antialiased display (jaggy-free)||X|
|Realistic Visual Style||X||X||X|
|Watercolor Visual Style||X||X||X|
|Illustration Visual Style||X||X||X||X|
|Monochrome Visual Style||X||X||X||X|