Autodesk Land Desktop 200631 Jul, 2005 By: Andrew G. Roe,P.E.
Tools for site development and civil engineering
WITH THE LATEST RELEASE OF LAND DESKTOP, Autodesk updates a mature product for land development design while maintaining compatibility with the latest release of AutoCAD. Long-time users looking for new discipline-specific features won't find many. But because Autodesk Land Desktop is built on AutoCAD and Autodesk Map 3D, the AutoCAD 2006 features alone offer productivity gains to numerous disciplines, making this an enticing upgrade.
Land Desktop 2006
Dynamic blocks are one of the more intriguing new features in AutoCAD 2006. Land Desktop puts this new feature to work with its Block Editor (figure 1), allowing quick layout of repetitive items such as parking lot stalls and islands. Using Block Editor, you can build one stall and quickly replicate it, changing it on the fly as it's inserted. Dynamic blocks are assigned parameters, such as linear and point properties, and actions, such as array behavior. The upshot: by inserting a dynamic block and dragging the cursor onscreen, you can graphically lay out a series of parking stalls in one fell swoop (figure 2).
Figure 1. Land Desktops Block Editor can create commonly placed features such as parking lot stalls.
Land Desktop 2006 also includes a new set of CAD drawing standards for both Imperial and metric projects, helping simplify project setup and adherence to office standards. Prototype drawings are provided with standard layer definitions, point group definitions and other settings.
Figure 2. Dynamic blocks can be used to graphically lay out a series of parking stalls.
If you missed the 2005 release of Land Desktop, it improved such mainstay features as alignment tables, allowing more options and dynamic resizing when inserting tables into a drawing. It also introduced the Detail Component Manager, which creates and saves construction details such as curb and gutter, fire hydrants and storm drainage pipe for reuse in multiple projects. Somewhat like dynamic blocks, detail components are inserted with parameters such as pipe diameter, so you can select from numerous variations of one detail.
Along with its recent additions, Land Desktop maintains its solid core of base features for site development and civil engineering. A plethora of options are available for creating, importing and editing coordinate geometry points, alignments and parcels. Once geometric elements are created, numerous options are available for labeling the elements, although users always seem to clamor for a bit more flexibility. Like other Autodesk products, the Land Desktop object model is readily accessible through VBA and Visual Lisp for users interested in customizing labels and automating repetitive tasks.
Land Desktop also provides robust terrain modeling tools for creating 3D surfaces of existing and proposed features. In addition to relatively painless creation and editing of TINs (triangulated irregular networks)—the backbone of 3D surface models—users have several options for creating and managing contours, breaklines and other terrain model features. Various options allow display of slope arrows, instantaneous slope determination and color banding of models by contour range (figure 3).
Figure 3. 3D models display contours with banding to show elevation ranges.
After existing and proposed surfaces have been modeled, earthwork volumes can be determined with three different methods:
- 1. the grid method overlays a horizontal grid on two surfaces and determines prismoidal volumes of all grids,
- 2. the composite method creates a new composite surface based on two other surfaces and calculates volumes based on the elevation differences between the two surfaces, and
- 3. the section method cuts cross-sections through two surfaces and generates volumes either by determining prismoidal volumes or by averaging the end areas of the sections.
Volume calculations can be compared in a report form that, though not pretty, is functional and can be printed or exported to a text file (figure 4). Land Desktop also generates reports for alignments and field staking.
Figure 4. Earthwork volumes can be compared using various methods.
On its own, Land Desktop is not geared for detailed design of roadways or storm drainage systems. For that, you'll need the Civil Design Companion, which is now packaged as an add-on component of Autodesk Civil 3D. But long-time Land Desktop users reluctant to learn Civil 3D need not despair. The Civil Design Companion works with Land Desktop, letting you avoid—for the time being—the paradigm shift to Civil 3D, which takes a more object-based approach to civil design (See Cadalyst March 2005 http://aec.cadalyst.com/0305civil3d).
With the dual product paths of Land Desktop and Civil 3D, many new and long-time Autodesk customers are wondering what the future holds for Land Desktop. Civil 3D, first released in 2004, has fueled speculation on whether Autodesk would maintain both products. For the time being, Land Desktop "will continue to be released as long as our customers require it for their business," says Annaleis Hogan, Autodesk's product manager for Land Desktop. She acknowledges "an enormous transition to Civil 3D," but adds that Autodesk is "committed to allowing our clients to decide when it is right for them to migrate to Civil 3D."
While the two products coexist, Autodesk has provided import/export capabilities for sharing data between Land Desktop and Civil 3D and vice versa. Because Land Desktop stores project data such as points and alignments in separate project files and Civil 3D stores data within the drawing, you can't seamlessly access data created in one product with the other. You can open Civil 3D drawings in Land Desktop and interact with Civil 3D objects to a limited extent using an object enabler, or you can extract Civil 3D data for import directly into Land Desktop. In both progams you can export data to LandXML format and then import the data into a variety of software environments.
Even with the apparent shift toward Civil 3D, Land Desktop alone has plenty to offer civil engineers, land surveyors and other land development professionals. It's generally a stable, dependable product with decent documentation. It's a known commodity that has proven capable for both preliminary and final design as well as plan production. Third-party add-ons are also more plentiful than with Civil 3D (www.autodesk.com/landdesktop-tools ).
Land Desktop's future hinges largely around the adoption rate of Civil 3D, which is gaining favor for its dynamic updating of project elements as design changes are made. But with a significant learning curve, Civil 3D also has its detractors, so Land Desktop appears to have a secure place for the near future.
Andrew G. Roe is a licensed civil engineer and president of AGR Associates, Inc. He is also author of Using Visual Basic with AutoCAD, published by Autodesk Press. E-mail him at email@example.com