File Performance – Self Audits

Projects are routinely audited, or at least reviewed on the BIM Server to maintain a reasonable quality of model performance and accuracy. There are specific areas of the audit that are responsible for file performance. Some of these audit sections are worth paying attention to because they can affect file navigation, others can impact general teamwork performance. In any case, these areas of the audit are worth periodically reviewing, even between formal audits.

The areas that need to be self audited are:

  1. The Library Manager
  2. The Library Loading Report
  3. The “Error” Report
  4. The Drawing Manager
  5. Solid Element Operations
  6. Total Model Polygons
  7. Attributes

Library Manager

The Library Manager needs to be periodically reviewed for organization. A disorganized Embedded Library is difficult to maintain, manage, and review. More than the organization, the contents of the Embedded Library are a critical element to file performance. Because the E/L is part of the file, rather than linked to the file like a BIM Server Library, it directly impacts the overall file size; even if content is not placed in the model. Ideally, .gsm content embedded in the file should be less than 10 MB and images used for surfaces should be less than 1 MB. These should be the targeted max for embedded library content. The more frequently an object or image is going to be used in the model, the smaller the file size should be.

Library Loading Report

The library loading report will appear when first opening/joining a file if there are any library issues. These issues may include missing, duplicate, or substituted library content. It may seem like this is just something to close out of and ignore, but this palette is warning that your model may be suffering from poor performance and accuracy. For more on the Library Loading Report, see this WWABIM post here.

Error Report

The report tab will come up when there is processing error in any non-plan model Viewpoint. Like the library loading report, it may be tempting to ignore this tab, but this report is a warning that your model is suffering from invalid geometries, missing attributes, or other errors that can not be resolved. If there are too many errors in the model, the result can be beach balling, slow send/receive, and slow navigation between Views. To review how to clean up Error Report content, see this WWABIM post here.

Drawing Manager

The Drawing Manager often suffers from missing content. Although missing content here may not slow a file down noticeably, the drawing manager is a good place to review externally linked content such as .dwg & .pdf files that have been dropped onto layouts. The drawing manager is a good place to review the update status of content on layouts, which can speed up layout book navigation. This is also a good management tool for tracking external content’s paths to review linked content file size. Linked drawings with large file size can slow the model significantly, and even more so if large files are embedded in the drawing manager. Always review pdf/dwg file size before embedding in the drawing manager. For more information on the Drawing Manager see WWABIM posts here and here.

Solid Element Operations

Solid element operations have been reviewed in past WWABIM posts here, here, and especially here, as well as in a previous internal DD L&L. In running self audits, any element with more than 100 connections should be reviewed, with any unnecessary targets, operators, or other connections removed.

Total Model Polygons

The most important aspect of a model’s performance is often the number of visible polygons. But even if layer and view settings are carefully managed and reviewed, you may run into situations where the entire model needs to be viewed, or may be accidentally viewed. If there are too many polygons in the model, this may result in an slow file performance, beach balling, file or computer freeze up, or even a file crash. With our current hardware, we should be aiming for no more than 5,000,000 polygons for a standard file.

It may not always be a clear line, since the source of polygons as important a role in file performance as the total polygons. For example, in some basic tests and overall experience, 60,000 polygons from a single mesh can perform worse than 1,000,000 polygons from objects. Also, 3,000,000 polygons from a single library part (object tool) placed several times will perform significantly worse than 3,000,000 polygons from 50 different library parts. In general objects contribute to the most polygons, but GDL also handles polygons significantly better than other tools. Overly complex mesh elements and excessive use of morphs can be a bigger performance issue to a file than objects.

Attributes

Attributes can have a huge impact on file performance, as well as document and output file sizes. A large, complex, custom cut or drafting fill can result in an incredibly large pdf or dwg file; in some cases so much so that the files can not be emailed or, in many cases, even printed/plotted. Additionally, custom profiles can result in poor model performance if not properly applied to the model. Profiles applied to walls should be used sparingly, as the intersection between walls results in excessive polygons and slow model performance. Custom profiles are better applied to beams, instead of walls.

The last part of attributes that should be self audited is the naming and file size of the attributes. If surfaces are using large images, it can slow the file down (see Library Manager above). Beyond the image size, the image naming of surfaces is critical to BIMx output. See the WWABIM article here and here for more information on BIMx surface errors.

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