By Jerry Laiserin, FAIA
One of the great frustrations in computer technology for architects, urban planners, contractors, and builders is the difficulty of combining computer descriptions of buildings with information about the site and terrain that those buildings occupy. To facilitate this process, Cad Easy Corp. has developed EasySite, a $495 plug-in for Autodesk's AutoCAD program that quickly and automatically contours 2D AutoCAD drawings, scanned paper maps, or USGS DEM files and arcs into 3D surface models.
EasySite fills an important niche in architecture, engineering, and construction (AEC) applications. Typically, buildings are drawn and modeled in vector-based CAD software, in which lines, surfaces, and volumes are defined by mathematical descriptions. In AEC, the most widely used CAD program for designing and describing buildings is AutoCAD.
|EasySite2.0 quickly builds 3D terrain models and road profiles (top), renders the results (middle), and allows for the insertion of 3D building models and additional items such as signs or trees (bottom). Images courtesy Cad Easy Corp.|
Landforms and property boundaries, on the other hand, typically are recorded on maps, often with associated data points (spot elevations) or topographic information (contour lines). Map images usually are raster-based, which creates a conflict with vector-based CAD building models. There fore, anyone wanting to visualize and study a building in relation to its site first needs to convert topographic maps or surveyed elevation data into a CAD-compatible 3D mesh that accurately models the terrain.
Matching a building to its site requires more than just an accurate terrain model, however; it also requires the ability to ad just and modify the terrain in order to properly set the building and its appurtenances-the surrounding roads, drives, walks, parking, fencing, signage, lighting, plant materials, and so forth.
As if all that weren't enough of a chore, the manipulation of landforms in the computer also must obey real-world rules and constraints for factors such as the maximum slope or grade of roads and ramps, or the greatest permissible pitch of unsupported soils of varying compositions. Surface drainage patterns must be accounted for, in both planted and paved areas, and inlets to subsurface drainage systems must be identified and accommodated. Paving profiles and the ways they intersect also must be realistic and rules-based (for example, two crossing streets of different widths, each with their own crown heights, gutters, curbing, and so forth).
A number of software products on the market ad dress these needs, including Autodesk's Land Develop ment Desktop, EaglePoint's LandCADD, and Nemetschek NA's VectorWorks LandMark. But, for many users who are primarily in the building design business, as opposed to full-time land development, most such products have comprehensive features they might not need, resulting in unnecessary cost or learning time for the narrowly defined task at hand.
EasySite is tailored to fill this market niche. Be cause it's a low-cost add-in to AutoCAD, it's not on ly easy to buy, but easy to learn and use because its menus integrate with standard Au to CAD men us, and its commands work like AutoCAD commands (with which EasySite's users are likely to be already familiar).
A typical EasySite session starts with an imported topographic site map, from which each contour line is "pulled" up to its proper height on the Z-axis, automatically generating a 3D mesh of the terrain (actually, a Triangular Irregular Network, called a TIN, layer that represents the "topo" faces).
Next, the "footprint" of a CAD building model, in AutoCAD DWG format or imported from any other CAD program via DXF, can be dragged and positioned in the desired location and orientation and simultaneously set to the proper benchmark elevation. When siting a building on a slope, EasySite automatically generates new grades to cut the floor plate into the uphill slope and fill in the downhill slope (the default cut and fill can be edited).
Similar intelligence applies to drawing roads, driveways, and sidewalks across uneven terrain: EasySite limits the maximum gradient in the pavement while generating balanced cut and fill as the right-of-way crosses the landforms. User-controlled smooth ing routines also can be applied to fine-tune the finished grading of land contours.
Meanwhile, roads and the like are drawn by their centerlines, then a profile (cross-section) is applied, either from a supplied library or defined by the user. Some manual trimming, such as filleting the radii of intersecting curb profiles, still is required when two EasySite roads intersect. Stock libraries of textures, plants, street furniture, cars, and other items ship with the program and can be supplemented by third-party collections of AutoCAD-compatible blocks and textures.
After the terrain has been modeled, the building model sited, and all sitework and landscaping defined, the result can be viewed in Easy Dview mode, a customized version of AutoCAD's Dview, or Dynamic View, command. EasySite models also can be viewed through Cad Easy's own QuickShade (included), which is somewhat easier to toggle on and off than using AutoCAD's native shader. Or, models can be exported for further rendering in Discreet's 3D Studio Max or in the Accurender program from Robert Mc Neel & Associates.
Overall, EasySite's low cost, ease of use, function-specific intelligence, and Auto CAD compatibility make it a worthwhile addition to the software toolkit of any designer who needs to place building models on building sites.
Architect Jerry Laiserin, FAIA, provides strategic consulting services to architects and their technology providers. He can be reached at firstname.lastname@example.org.
Minimum system requirements: AutoCAD (release 14 or higher); any AutoCAD-capable Windows PC
Cad Easy Corp.