AutoCAD User Group Of the
Pocono'sAutoCAD User Group Of the
Pocono'sby
Teresa Pineda Davidson and Ted Green
The H1 Kawela Bay Hotel project has more than 1,000,000 square feet of covered space, including 650 guest rooms, three restaurants, retail space, ballroom, dinner showroom, function room, and meeting rooms. Other facilities include a health club, childrens activity center, young adults center, and two parking structures housing almost 1,000 parking stalls. These functions are accommodated in 10 buildings laid out along a spine paralleling the curving shoreline.
DESIGN CONCEPT AND PROJECT DEVELOPMENT
A design based on a hill-town concept was chosen to support the many activities and functions offered by the hotel. Each building has its own character and identity but draws from a common architectural vocabulary. A pedestrian street winds between the buildings, binding them together and enhancing the hill-town atmosphere. A walk along the covered arcades is enriched with cascading fountains, flowers hanging from lanais, and the ocean in the background.
The H1 plans were first developed on AutoCAD in the late stages of the schematic phase. At that time, the entire multilevel campus was maintained in a single drawing file. However, it was obvious that the single file would become unmanageable as the drawings were developed into construction documentation. Late in the design development phase we created a formal layering scheme, naming conventions, and a blocking strategy to carry us into the construction document (CD) phase. One of the major strategy components involved dividing the buildings into quadrants and using these quadrant plans as the basis for plans at other scales.
Drawing these quadrants oriented to the sheet just as they were in the overall site plan allowed us to develop the plan set as a large-scale 2D multilevel system. Each quadrant of each building dovetailed with its neighbors in the master coordinate system. The center of the entry drive circle was chosen as point 0,0, the reference point about which everything related geometrically. Thus, to see adjacent building quadrants, a designer had only to block in the appropriate drawing at a 0,0 World Coordinate System origin.
The design development drawing was dissected, and the layers were renamed. Special care was taken to maintain the overall site relationships between quadrants. Master drawings were developed for each building quadrant at each level.
CAD SYSTEM ORGANIZATION
Group 70 has 45 Macintoshes, eight IBM clones, and four SPARCs; nine are CAD stations running AutoCAD Release 10. All the machines are connected by a heterogeneous network running AppleTalk, Sitka TOPS, Sun NFS, and 3Com protocols on a star-configured, unshielded twisted-pair wiring system.
Giving the hardware nicknames made keeping track of maintenance and upgrades easier; it also put a friendlier face on the system. It did not seem sensible to name the systems after staff members because assignments to particular stations changed daily. Instead, the Macs were named for fruits and vegetables, SPARCs for spices, and PCs for nuts. Onion was the name of the server for the H1 hotel project, and the team was filled out with Basil, Garlic, Oregano, Avocado, Orange, Tomato, and Lime. To facilitate multiple access to the drawing files, they were all stored on a single file server. With as many as 11 different users of the overall H1 CAD system, it was important to avoid double-usage of any single drawing. In the absence of Release 11s network facilities, we instituted a simple yet effective system. Each user had a checkout folder in the project directory. Before opening a drawing, they were required to move it to their checkout folder. All drawings remained in the project directory; this made it plain which drawings were in use by whom, and any missing drawings could easily be located by listing the checkout folders.
All the drawings resided in a single project directory with subdirectories as follows:
levels: composite site plans of all levels at 1 inch = 40 feet.
parking-plans: parking floor plans at 1 inch = 20 feet.
quad-plans: building floor plans at 1/8-inch = 1 foot.
unit-plans: enlarged plans for the guest-room types. q-scale: enlarged plans such as cores and
restrooms at 1/4-inch = 1 foot.
plan-blocks: typical architectural blocks used in plans such as doors, columns, guest room unit
types, lanai types, etc.
elev-sheets: several elevations composed to create 1/8-inch drawing sheets.
elevations: individual building elevations; this allowed more than one person to work on various
elevations from the same sheet at once.
elev-blocks: typical blocks pertaining to the elevations.
symbols: drawing symbols such as room names and numbers, door numbers, section cuts,
details, etc.
grid-blocks: typical structural grids, column bubbles, and overall dimensions for building plans.
elev-grid-blocks: typical structural grids for elevations.
site-blocks: blocks generated by a script that eliminates detail information from the quadrant
plans such as notes and symbols prior to insertion into the levels plans.
buildings: drawings that are updated periodically by a script that combines several files from the
quadrant plans to show buildings as a whole. checkout: user subdirectories; for viewing
drawings.
CONVENTIONS
Files were used interchangeably between Macintosh, DOS and SPARCstations in-house on a daily basis and with other CAD systems such as VersaCAD and MicroStation periodically. Giving proper consideration to a naming convention for files guaranteed fewer headaches during the life of the project. DXF translations with consultants and exchanges across the in-house network required the following rules of thumb:
1. Names should contain eight characters or less with no commas, slashes, or periods (DOS).
2. Always use lowercase (SPARC).
3. If working on a Mac, add the extension .dwg when defining Wblocks.
These rules combined with the abbreviations assigned to the quadrants and their corresponding subdirectories resulted in short, patterned filenames (e.g., q-kce-2.dwg for the 1/8-inch-scale floor plan of Kahana Court East, Level 2 in quad-plans or s-kce-2.dwg for the corresponding site plan element in site-blocks).
Layer names followed the CAD Layer Guidelines developed by the American Institute of Architects. It is hoped these guidelines will gain popularity throughout the design industry. On the H1 project they provided a logical and practical way to expedite translation and file sharing. Team members could easily understand the structure of the drawing file and apply the layer definitions accurately. Strict adherence to these file- and layer-naming conventions was imperative, because scripts were used to automate tasks. For instance, revised blocks were inserted into multiple drawing files, and stripped versions of the quadrant plans (removing notes, symbols, and dimensions) were created prior to insertion in the levels plans. These scripts were generally run at night without supervision.
Group 70 adopted the AIAs long format where the layer name is defined by three groups:
1. The major group: one character, defines the discipline (A for Architecture, S for Structural, etc.).
2. The minor group: four characters, designates systems (a-wall, a-door, a-note, etc.).
3. The modifier group: four optional characters, can be used to break down the minor
groups into subcategories (a-grid-line, a-grid-dims, etc.).
OTHER STRATEGIES
In a strategy similar to that used for the floor plans, elevations were created by combining blocks. The parts to the whole concept proved effective for instance, when the design of a rail type changed. The rail could be redefined and reinserted globally, thus modifying all the typical bays that were affected. This strategy is only effective, though, when the block is redefined in every file in which it occurs. The rail type was a nested block within the typical bay. In turn, the bay was nested in the elevation, which was nested in the elevation sheet. The redefinition must occur globally. Careful coordination and documentation of the drawing structure and the block libraries was required for the success of this strategy.
OPPORTUNITIES FOR IMPROVEMENT
At Group 70, quality enhancement is given high priority. With as many as 11 users, achieving document uniformity and consistency required the enforcement of drawing guidelines and standards. Two levels of communication are typically required: project-specific conventions and firmwide CAD-related conventions. It is essential to maintain a current block log documenting the use of shared common blocks. At one point in the H1 project, the directory plan-blocks contained an enormous number of blocks for doors, which in many cases defined the same type of door drawn in different ways by different users. This became a problem when nested blocks were updated using a supposedly duplicate door definition. The nested blocks got confused, and the doors would appear rotated or mirrored. Locating and correcting the problem required a tedious trial-and-error search for the correct block. This problem was aggravated when it involved mirrored blocks. Not being able to explode mirrored blocks made it more difficult to backtrack to the correct name and definition. With proper block documentation, this kind of problem can be eliminated.
Mirrored blocks were also a nuisance when drawing the partial adjacent quadrants shown beyond the match lines on each quadrant plan sheet. It is a Group 70 CAD convention to draw all adjacencies on layer a-adjt so that it will plot with the lightest line weight. The adjacent areas were started by inserting the stripped-down version of the adjacent quadrant from site blocks. Then they were exploded and edited to show only the parts immediately adjacent. All entities were then changed to layer a-adjt. Since the mirrored, nested blocks could not be exploded and were typically not created on Layer 0, the blocks had to be mirrored, exploded, and mirrored back as single entities. Only then could their properties be changed.
The moral is to remember the reasons why CAD is more productive than manual drafting. One reason is that when set guidelines are followed, drawing files can be manipulated to serve multiple purposes. But users have to be conscientious about the process and follow the guidelines. CAD will not be efficient if the CAD team does not understand how to use the system effectively without duplicating labor.
Another important concern is the appropriate use of blocks. When should blocks be exploded, and when should they be preserved as blocks? A block, by definition, is a group of entities combined into one to be used repeatedly. A group of entities may belong together and occur only once in any particular drawing, but be used in multiple drawings (e.g., a structural grid). Is it more efficient to redefine it every time a minor change takes place or should it be exploded, forcing minor changes to be edited in each drawing? (Release 11 minimizes this problem with reference files.)
Hatching is an inefficient task that needs improvement. Generally, files double in size, and hatching patterns tend to leak out because entities overlap or do not close. For the H-1 Hotel, three material patterns were required for structural coordination: concrete, precast concrete, and concrete masonry units. Because the buildings were drawn at varying skewed angles to the sheet border, each pattern angle had to be defined relative to the predominant angle in each file. Hatching was tedious because often walls had to be traced over with Plines. To keep the files as compressed as possible, repetitive patterns were copied or arrayed instead of hatched for each individual area.
File sharing among the consultants various CAD systems required three different formats: DWG files on 3.5-inch disks; DWG files on MS-DOS 3.5- or 5.25-inch disks; and DXF files on 3.5-inch disks.
The number of files required meant much time and many disks. The DXF files were created using a script routine that freezes unwanted information for consultants. Although file sharing required an extra effort, the process allowed coordination while the design was developed and solidified. Furthermore, the file structure enabled consultants to manipulate the files to meet their requirements. At Group 70 we have chosen to rely on reproduction services for plotting rather than invest in expensive equipment in-house. For each plotting run of the 185 files, different methods were considered depending on purpose, time frame, and cost. The plotting options available locally were electrostatic on vellum or one-sided mylar and pen on vellum or double-sided mylar (pencil plots were available but were not used for H1). Electrostatic plots are fast but costly. Pen plots, on the other hand, can be time-consuming, but they cost about 40 percent less than electrostatic. For the record drawing sets, pen plots on mylar were chosen because of their inherent durability and graphic quality. Because of the time factor in pen plotting, small batches of drawing sheets were committed to plot sequentially to complete the set while providing time for coordination and quality control.
The H-1 Hotel project, with all its complexities, tight deadlines, and shifting design parameters, was successfully documented with the help of AutoCAD. The system will be upgraded to Release 11 now that it is available for the SPARCstation. With the enhancements available in Release 11, such as reference files, plot windows, and network support, even greater productivity can be promoted in the design process and further excellence achieved in the design documentation.
Teresa P. Davidson, AIA, is an architect and Ted Green is an associate and MIS manager at Group 70 Ltd. in Honolulu.
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