AutoCAD

What is VI Doing for Brown?

4 Jan, 2008 By: Bruce Jones

The huge expansion of a UPS sorting facility leads to lessons learned about the extensive use of Xrefs, file size management, and large file plotting.


More than two years ago, VanDerLande Industries (VI) of the Netherlands won a contract to increase the processing capacity of the United Parcel Service facility in Louisville, Kentucky. Because VI had completed the bulk of the existing system in 2002, the company was chosen as the contractor for the new project. The project was to be spread across multiple timed phases, coordinating with the construction of two additional buildings by URS, a global engineering and construction firm. The full expansion project is developing over approximately four years.

This secure UPS facility currently occupies more than 16 acres next to the Louisville International Airport and contains more than 40 miles of conveyors used to sort packages. The conveyors shuttle parcels from one source (usually airplane or truck) to another, and on to their destinations. The "in from source," sort, and "out again to destination" process takes place in two, four-hour cycles, six days a week. Installing the 40 miles of new conveyors between sorting cycles each day and on weekends is a logistical nightmare.

Leading up to installation, the engineering challenges of this project were tremendous as well. But the process we developed proved successful, and what we learned regarding extensive use of Xrefs, careful file size management, and large file plotting are lessons that can apply to many other projects of this magnitude.

Software Selection
Planning for this project began with resurrecting information from the 2002 building project. Original designs had been drawn in 2D CADAM from Dassault Systemes. Partially because of the volume of site engineering that had taken place during and since the first project, and partially because of the creation of an in-house custom conveyor line construction tool (called VILA) by VI programmers, the decision was made to build the newer project as a 3D model in AutoCAD. The VILA add-ons include the use of standardized parts, which helps maintain CAD standards -- and eventually bill of materials (BOM) standards -- throughout the project.

Conversely, extensive investment of time and training in VILA meant that VI didn't consider other software options that might have offered more desirable functionality, such as Autodesk Inventor and its ability to assign constraints. This situation also delayed the move from AutoCAD 2004 to 2007. VILA, in addition to its industry-specific conveyor building tools, contains additional functions for cleaning files; bulk conversion of system features (such as the single pick tool to remove all supports from an entire conveyor line); and custom label-generation features. This toolset became essential for efficiently handling a large project, both for maintaining standards and creating lean AutoCAD files that could be plotted within the 2-GB memory limitations of AutoCAD's plotting engine.

 

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The VILA-constructed and -controlled model adds dynamic design capabilities to AutoCAD.

Blending Old and New
The existing system had undergone extensive site engineering both during and after completion, and -- as is typical of such projects -- no accurate, as-built drawing set was maintained. A debate ensued regarding whether to use expensive scanning and documentation systems to record the system in situ, or to take on-demand site measurements and transfer them to the AutoCAD models at the transition points between the old and new conveyors. The latter strategy was chosen. Resident site-engineering personnel run a shuttle with dimensional and slope information from the active system to a site trailer, and transfer that information using e-mail and FTP servers. Layout engineers and designers in the VI-UPS project design centers in Marietta, Georgia, and Veghel, The Netherlands, can then access that data.

During the original project, the building had been divided into named sections, so to maintain consistency this same named grid program was adopted and expanded for the current project. The facility is divided into wings (load-unload outriggers projecting from the main structure; and north, south, and grade lane core structures). These large areas are subdivided into lettered blocks, and those are subdivided (by drawing number) into the four floors or levels of the system. Because the installation is time-phased, distinctions are made between phases through layer naming. Dynamic viewing of the model was accomplished using NavisWorks JetStream v5. Only in the postcompletion debriefing will the wisdom of this system become clear; for now, it works.

 

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NavisWorks JetStream v5 view of a small corner of the facility.

 

 

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The complexity of the project demanded special handling. This view shows two of the facility's more than 60 subdivisions.

Crash Course in File Management
The need for file management was clear almost from the beginning. AutoCAD's Options / System / Single Drawing Compatibility Mode feature immediately eliminated many of the crashes caused by overtaxing the RAM and virtual RAM drives, and the feature is used almost universally. But the physical plant structures, main vertical and horizontal supporting structures, subsystems, electrical cabinets, interconnecting lines, and existing lines demanded their own files. These were then Xref'd into master files, which began to crash regularly. Those files were further subdivided according to gross areas of the building, then subdivided again into smaller working divisions. The wisdom, which has proved sound to date, was that breaking up a large file into smaller ones as needed would be easier than starting too small and trying to combine files later.

Problems with managing changes within this process emerged as individual layout engineers chose to test design changes or create what-if scenarios for client meetings, then add the results back into the larger model. Overwrites occasionally caused confusion with the interim work done by other designers. These problems were dealt with by the shared use of a simple alphanumeric revision documentation system. Each person who pulls a file advances the revision number and locks the file. Sharing the critical or most frequently modified models is done one-on-one. To accommodate this dynamic interaction, the core design engineering staff was moved into a single, large office space.

Plotting the New Course
This modeling, adding, and subtracting Xrefs keeps file sizes manageable and reduces file regeneration time. It also reduces crashes, maintains document integrity, reduces interpersonal friction, and works surprisingly well overall -- that is, until the system comes up against the proverbial immovable object: plotting the monstrous drawings. The firm implemented several procedures to help manage the plotting process reasonably. Automatic file cleaning (upon opening each file by VILA), as well as regular hand cleaning by operators, helps curb the residual garbage created by constant design revisions. Before the drawings are plotted (from paper space), the following preparations are performed:

  • Unload any Xref that does not actually appear in the DVIEW window.

     

  • Break the plotting area into four or more viewports and individually manage the Xrefs that appear in each viewport. (Multiple smaller viewports hide and plot more efficiently than a single huge viewport because of the way AutoCAD handles pending operations in the hide engine.)

     

  • When necessary, use the Xclip function on the model, exposing only the area that will show in the Paper Space viewport.

Two additional practices have shown improved plotting success with the largest drawings:

  • Open the drawing to be plotted and press Escape after the Xrefs are loaded, as the model starts to regenerate (which requires plotting from a "blind" screen).

     

  • Set the Plot window toggle to Plot in Background, then close the AutoCAD window. (When a drawing is loaded, it occupies memory; when it is plotting, it again reloads the same primary file, plus all the Xrefs, into memory.)

Managing such a project eventually involves passing information from the designers and engineers to the documentation specialists and order processing personnel, starting with generating a BOM, cut lists, standard parts list, and hardware list. These tasks are accomplished via DPDII (customized by VI) and CAPE, another VI-created software system, independent of AutoCAD but deriving its parts database from the AutoCAD file output.

VI is not the only vendor on site, so coordination with other vendors is an additional consideration in the process. In these times of standardization, we still work with steel and physical plant contractors in 2D, using other CAD software, and of course have all the headaches that a team of people who don't speak the same CAD language are bound to encounter.

Customization is Key
Despite all the obstacles -- working around five years of site revisions and outdated junction-point data; huge, almost unmanageable file sizes; technical difficulties with both hardware and software; and interpersonal coordination challenges -- the project is well under way and running on schedule. VILA has restored my faith in the value of customization. The myriad issues we faced coordinating the old and the new have rejuvenated my belief in the need for quality as-built drawings as the final step in any engineering or architectural job, or high-end scans of existing equipment as a starting point for expansion projects.

Constant communication in this project -- for engineering and educational purposes -- has shown me that much of the value of engineering is based on the outcome of productive meetings of minds. My exposure to the extended use of Xrefs, careful management of file sizes, and learning new tricks to make large-file plotting more reliable have increased my viability as a CAD user. What VI is learning in the course of this project for Brown has applications far beyond this single contract.


About the Author: Bruce Jones


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