Autodesk Civil 3D (Cadalyst Labs Review)31 Jan, 2007 By: Andrew G. Roe,PE
Moving closer to becoming the production tool of choice.
A smart product got even smarter when Autodesk rolled out Civil 3D 2007. The model-based software pushes the use of intelligent objects even further than its previous versions did and offers enough practicality for real projects. But is Civil 3D really ready to shine as the production tool of choice for civil engineering professionals? Engineering firms and public agencies around the globe are asking that question, as they cling to Autodesk's Land Desktop as their primary production software and only eye Civil 3D as the wave of the future.
Autodesk Civil 3D
Civil 3D's intelligent objects and dynamic modeling capabilities have gained popularity since the software's initial release in 2004 (see Cadalyst, March 2005, p. 36). Instead of relying on generic CAD entities, Civil 3D provides real-world objects that maintain relationships with other objects. For example, an alignment object is a combination of lines and curves that collectively defines the horizontal location of a project component, such as the centerline of a road. If you edit an alignment, the changes are automatically reflected in all related objects, such as profiles and cross sections.
Although Civil 3D has wowed many users with its swift roadway and site-modeling capabilities (figure 1), the civil community has balked at widespread adoption, primarily because of the product's steep learning curve and key feature gaps. Some feature gaps have been addressed in this release, which could jumpstart the product toward becoming a full-scale production tool.
In the Pipeline
One key 2007 enhancement is the ability to design pipe networks. You can create 3D models of storm sewers, sanitary sewers and other utility systems and handle them as intelligent objects. You can locate drainage structures in plan view along a roadway, connect them with pipes and display pipe-network components in profile and section views. If you make changes to pipe networks in plan view, the systems are dynamically updated in the profile and section views. A part builder can help build custom manholes, inlet structures and pipe types, or you can choose from a prebuilt library of standard components.
Figure 1. Civil 3D can model difficult situations, such as this roadway on the side of a large ridge with a new road coming in from the lower part of the ridge. The intersection is skewed, and the two roads have a large elevation difference. Image courtesy of Autodesk.
Along with pipe-network design, you can perform interference checks to identify where pipes or structures physically conflict or are too close to one another. Now the interference check is a Civil 3D object, with styles and settings available to determine how conflicts are identified and displayed (figure 2).
Civil 3D doesn't include H&H (hydrology and hydraulics) capabilities, so you won't be able to determine storm-water runoff or pipe sizes within the software. But the product performs well at geometric design once you have sized pipes and structures. As with any product, you'll encounter situations that the software doesn't handle, such as automatic labeling of inverts at pipe crossings and inclusion of service lines within a system. Like other Autodesk products, however, Civil 3D is customizable through VBA, Visual LISP and .NET, allowing you to write routines that handle specific situations.
Civil 3D 2007 also provides capabilities for working with field-survey data. In previous releases, you had to use an external package, such as Autodesk's Survey module in conjunction with Land Desktop, to download, create, analyze and adjust survey data.
Figure 2. Conflicts with underground piping can be identified using interference checks.
Civil 3D uses two primary objects for surveying: the network object, which represents a survey network or traverse, and the figure object, which represents a survey figure such as a plat. Within a network, you can view field observations from a given setup in both graphical and tabular format (figure 3). Unlike other Civil 3D data, survey data and figures reside in a survey database, meaning they can be accessed via multiple drawings attached to the same survey database.
You can perform a variety of surveying calculations in a command window that records input and output (figure 4). For field-traverse analysis, you can use tools such as the least-squares method to make adjustments in survey networks or individual traverses. You can draw and control field-located line work by using point descriptions or figure commands.
To convert field data to field-book files and import the data into Civil 3D, you can work with a variety of survey data collectors. But don't look for data-collection interfaces within Civil 3D: Autodesk relies on third-party tools, which can be linked to the Civil 3D Media Browser or obtained from the Civil 3D partner products Web site (www.autodesk.com/civil3d-partners).
Vaulting for Management
Civil 3D 2007 is the first civil product to include Autodesk Vault, a project management component that allows mul-tiple users to access project data and work in sync through project drawings. Vault stores designs in centralized locations and allows users to share access to Civil 3D objects such as surfaces, alignments, profiles and pipe networks (figure 5). While one user is working on a portion of a project, others can create read-only references to object geometry for use in other drawings. Points, which normally are stored within a Civil 3D drawing, can be saved in an external database when using Vault.
Figure 3. Survey observations can be displayed for a selected setup point and highlighted in the drawing.
Previously integrated with Autodesk's mechanical and electrical products, Vault may not be suited for all civil users. Some feel it's more geared to linear, repetitive processes than the project-specific nature of civil work. Time will tell whether civil professionals adopt Vault, or if they view it as just a nice feature that falls by the wayside. For users who choose to not implement Vault, Civil 3D 2007 also includes the project shortcut mechanism, which is a simpler application for project collaboration.
Other enhancements in Civil 3D 2007 include a new label object that consolidates separate label types for alignment and profile stationing, surface-spot elevations and section-view elevations, as well as notes, lines and curves. The new behavior allows you to reference other objects in a label.
The corridor object—one of the most impressive Civil 3D objects due to its linking of other objects such as alignments, profiles and sections—has been enhanced in 2007. In addition to providing dynamic modeling capabilities for roadways and other projects, you can now grip-edit subassemblies in a corridor section view. In other words, you can graphically change components such as curbs, sidewalks and pavement sections in cross-section view and automatically see the changes reflected in the corridor object.
Figure 4. Surveying calculations, such as inverse operations, can be performed in a survey command window that records input and output.
Other Civil 3D objects, such as points, surfaces, profiles and sections, also have been enhanced with various bells and whistles. Autodesk has steadily added features and capabilities to help make Civil 3D both a preliminary and final design tool. But gaps remain in key areas such as production drafting and data exchange. Interoperability with Land Desktop projects is generally solid, but items such as point data and earthwork volumes don't transfer seamlessly.
Occasionally, performance issues have dogged Civil 3D. Autodesk recommends a 3GHz Pentium IV processor or better with at least 2GB of RAM, and you may want to increase that for large datasets. The software has been known to bog down over time, indicating a possible memory leak. Autodesk says that is is working to address key feature gaps such as sheet generation and to improve general usability and performance on large projects.
Figure 5. Project management can be augmented with Vault, which stores designs in centralized locations and allows users to share access to Civil 3D objects.
Overall, this product has matured significantly and appears to be a rising star for civil engineering professionals. The learning curve is becoming less daunting as the overall knowledge base grows, although new users will still need to invest significant time to grasp the concept of intelligent objects and styles, which control object behavior. Perhaps the 2008 version (scheduled for release in early 2007) will address performance issues and enhance Civil 3D's credibility among those wary of object-based design. With a dose of patience and a realistic implementation time frame, Civil 3D's intelligent objects can also make you look smart.
Andrew G. Roe is a licensed civil engineer and president of AGR Associates. He is also author of Using Visual Basic with AutoCAD, published by Autodesk Press. Email him at email@example.com.