THE USE OF CADD INTERACTIVE SOFTWARE IN AN ADVANCED ESTIMATING COURSE

INTRODUCTION

Computers have long been used as a productivity tool in construction estimating. Beginning in the late 1960's, mainframe computers were used to increase estimator productivity and accuracy. Since then, estimating applications have expanded to include mini and microcomputers. Estimating software has evolved from specialty written programs for mainframe computers to spreadsheet and data base adaptations, keyboard data entry programs, device data entry programs, and, most recently, CADD interactive programs for the mini and micro computer environment. This most recent development adds the ability to obtain dimensional data for quantity take-off and pricing directly from CADD drawing files, either as an integrated module of a CADD program or as a stand alone program working with imported drawing files.

ESTIMATING SOFTWARE

Research has shown there are four types of software programs currently being used in the construction industry. These are general application programs such as spreadsheet and data base packages, estimating programs using a keyboard for data entry, estimating programs that incorporate digitizer/mouse take-off capabilities, and estimating programs that work directly with CADD programs and drawing files.[1]

General Applications Program

General application programs include spreadsheets such as Lotus 1-2-3 and data base programs such as dBase IV. Each of these programs offers some estimating capability: spreadsheets through specially created templates and macros, and data base programs through programmed applications.

Spreadsheets perform estimating procedures through the use of templates, the spreadsheet equivalent of a printed form, and macros, an internal program that automates template use. The template/macro combination provides for the structured entry, storage, manipulation, and reporting of estimate data. One such template/macro combination is reported in "A Lotus 1-2-3 Macro to Simulate Basic MC2 Estimate Procedures." [2]

Data base program estimating is done through the use of separate programs or applications, written and compiled in the internal programing language of the data base. Like spreadsheet templates/macros, these applications also allow for the entry, storage, manipulation, and reporting of estimate data; but, rather than forcing the data into a column and row format, the user is free to format entry and report forms to more closely meet his needs.

In both cases the estimating capability must be programmed by a user or professional programer, and, the data must be entered by keyboard.

Keyboard Programs

Keyboard data entry programs range from the minicomputer based MC2 to the microcomputer based shareware program PC Estimator. The typical keyboard data entry program consists of modules that store and manipulate cost data, establish program defaults, allow the entry and maintenance of basic project description data, the entry of quantity take-off data, the review and modification of take-off data, perform calculations, bid preparation and analysis, and report generation. Little preparation work is required other initial program set-up and the entry of company cost data.

Device Programs

Device data entry programs have modules similar to keyboard entry programs but provide a significant increase in estimating productivity by increasing the speed of the quantity take-off. The take-off devices used include any of a variety of mice or digitizer tablets. A mouse enters dimensions into the computer by running over the plans in the manner of a plan measure. A digitizer tablet is a plan table with an electronic stylus. Plan sheets are placed on the table and the stylus enters dimensions by pinpointing locations on the table grid. These dimensions provide accurate readings of the lengths, perimeters, areas, volumes, and numbers needed in the quantity take-off.

CADD Interactive Programs

CADD interactive programs also have modules to allow the user to store and manipulate cost data, establish program defaults, enter and maintain basic project description data, enter quantity take-off data, review and modify takeoff data, perform calculations, prepare and analyze bids, and generate reports. But, rather than entering data by keyboard or device, dimensions for quantity take-off are obtained directly from the CADD drawing files. The two programs of this type currently available are Generic Estimator and Timberline's Integrator. Generic estimator works as a module of Generic CADD, and Integrator as a module of AutoCAD. A description of the specific capabilities and procedures of Generic Estimator follows.

GENERIC ESTIMATOR

General Description

Generic Estimator is written by Generic Software, Inc. of Bothell Washington. The Estimator can be used alone or interactively with a CADD program. Generic CADD is the companion drafting program that interfaces with Generic Estimator to enable the Estimator to do quantity take-off directly from the computer drawings. The main focus of the paper will concentrate on the use of the Estimator and the interface with the CADD program.

The Estimator is a computerized job estimating and reporting system. The estimating section allows for 16 Divisions with up to 10 subdivisions, and 100 items per subdivisions. This gives the estimator 16,000 cost items per bid which can be priced. Each cost item can have up to 9 cost types, such as material, labor, equipment, supplies, etc. The final price operation is done by applying the markups. Their are up to 12 different markup items available. Some can be applied to the entire bid, while others can be applied to cost types or specific items.

The takeoff operation can be done by several methods. A calculator function allows the estimator to use the computer like a printing calculator and transfer the numbers directly to the cost item being determined. Quantities can be imputed directly into the cost item. If Generic CADD is available, area, perimeter, and count items can be transferred directly from the computer plan to the Estimator.

The report section has two main categories. The database reports which deal with the items, cost types, markups, divisions and subdivision breakdown, and can produce blank work sheets. The bid reports deal with takeoff, quantity/cost, material order, and bid reports. Basic reports already exist in the system and there is space available to customize individual reports.

Hardware

The hardware requirements of the Estimator is as follows:

Installation Procedure

The installation procedure is simple in that an auto installation program does most of the work. Several on­screen messages and questions appear during the installation procedure. You must be certain of the current configuration of the system to answer the questions correctly. This is especially important when trying to install Generic CADD, which is more dependent on the hardware, to properly display the information.

Once the installation program has been run the starter system is activated which contains the Estimator Tutorial Program. The complete system cannot be used at this point without executing the instant activation function which requires the user to verify the serial number. This serves as a security measure without becoming a major problem.

Documentation

The operation manual provided is organized and easy to follow. The manual covers various aspects of the program such as installation, computer basics, advanced activities and also contained a tutorial. The interface with Generic Cadd is also in the manual, but the operation of CADD is contained in the CADD manual. The use of CADD to do the takeoff is well explained and a basic drawing and takeoff tutorial is included. A glossary of terms used in the program is provided to define terms that are used by both the computer industry and construction industry.

Program Procedure

The program begins with a main menu that lets you decide which basic database you plan to use to takeoff and price your new project. The database can be an existing one or you can create a new one. The creation of a useable database and the accompanying codes and divisions is a time consuming and extensive operation. However, once in place, the takeoff and pricing procedures take advantage of the database.

The estimating section or BID selection allows the estimator to view the various items in several ways. A checklist format is the main method presented for speed and accuracy. A base checklist of all standard job items can be used to start a new job and the modification for a specific job can be done easily. The checklist uses the latest cost data from the database so that the costing operation will be done as the units are taken-off. Changing the cost factors can be done at any time during the operation so that the pricing can be adjusted to current quotes. The Estimator is flexible and allows the user to set up, review and update both the databases and take-off items at the same time.

The basic operation of the Estimator is through menus until is take-off is begun. Then on-screen windows are used to help track the estimator's work. The windows appear as an estimator requests information on specific items. Their original set of guidelines, equations, units and costs can be displayed and/or modified as needed.

The interface with the Generic CADD is provided to do take-off from plans. This operation requires the estimator to begin in the estimating program and then start the Generic CADD program. Once the plan is in generic CADD the first thing needed to check is proper dimensions or units. The computer will estimate distance based on these units so they must be correct. The interface uses a buffer that stores the values taken from the plan. There are two ways to do this operation.

First, is the boundary takeoff. This operation calculates perimeter and area from the selected points on the drawing. When points are selected the distance from one point to the next is added to get the perimeter. The last point selected should also be the first point selected to close the area for calculation. The values are placed in a buffer and their correctness has to be verified before they can be transferred into the estimate.

Second, is the count takeoff. If elements have been placed on the drawing by a component name, the computer can count these items. The process is to identify the component and place a  window around the area you wish to takeoff. The component is counted inside the window and again this unit will be placed in a buffer to be transferred to the estimate.

The transfer of the quantities from the CADD program to the Estimator was a little slow because each takeoff had to be transferred by going to the Estimator program then returns to the CADD program for more information. Since some numbers can be used for several items on the takeoff, some time can be saved. This time savings will also depend on the items in the takeoff and the breakdown of the project. The transfer is slow because the moving from the programs requires the loading and unloading of the programs.

The final procedure is to obtain the information to review for completion of the bid. This is done with the report selection from the main menu. The database reports allow you to view the information used to create the bid. The bid reports allow you to review the bid and check takeoff quantities, markups, and totals. There are enough reports to check the estimate and bid and other reports for material ordering and subcontract control.

The program is well organized and screen layout allows for easy operation and tracking. The takeoff operation is sometimes confusing when corrections or changes were being made. The changes appear to make duplicate entries which have to be erased. Overall, the program performs well and no major problems were encountered. 

Ease Of Use

Generic Estimator is easy to run and help is always available if a problem is encountered. The tutorial is easy to follow and allows the person to do things on their own to check other functions. The sample databases are large enough to provide a complete look at the program with sufficient detail. Overall the program is easy to use except for the creation of duplicate entries and not advising the user that this was being done.

The manual has some valuable advice that should be followed to prevent the estimator from getting discouraged. First is to plan the divisions and subdivisions completely before starting. A little planning can avoid a lot of wasted time. This planning should also include room for future expansion of divisions as item and jobs change.

Second is to enter a division or subdivision and then begin using the program on a small scale. This allows time for the estimator to become familiar with the program and its operation. The estimator can also use the program and obtain some benefit of the effort put into developing the database.

CLASS IMPLEMENTATION

Class Procedures

For the Fall Quarter of 1989 several projects were planner to give the students exposure to all of the capabilities a the Generic Estimator program. A budget crunch however, reduced the number of hours that the compute lab could be kept open. It was decided, therefore, to limi computer assignments to the Lotus templates and macro: that could be used at other computer sites on campus and to the Generic Estimator tutorial exercise: demonstrating CADD interactive estimating that would have to be performed in our own computer lab.

Class procedures, then, were to distribute copies o the exercises, demonstrate the exercises in class, and have the students perform the exercises during course lab time. The exercises had the students start the Estimator program, load a sample data base into memory, switch td the CADD program, perform the quantity take-off, transfer the quantities to Estimator, and price the item out. The exercises included the take-off of lengths, areas, and quantities. There was not enough time to teach the programs report functions, so the cost windows were printed using the computer's print screen feature.

The student's response was very favorable. They had few problems following the instructions in the tutorial; and they were interested in using the program for additional exercises.

Though this only began to expose the student td the capabilities of Generic Estimator, it did give the students some exposure to the capabilities of CADD interactive estimating software.

SUMMARY AND CONCLUSION

Research has shown that there are four types or genera categories of software programs currently being used it the construction industry. These are: 1) Genera Application Programs such as spreadsheet and data base packages; 2) Keyboard Programs for estimating data entry; 3) Device Programs that incorporate digitizer/mouse take-off capabilities; and 4) CADD Interactive Program; that work directly with CADD software and drawing files. [2; The reader should note that these groupings are hierarchy of programming sophistication and is not a quality ranking. A construction company may find Genera Application Programs not only adequate but desirable. For more information derived from the aforementioned research please see the accompanying tables.

Generic Estimator and Generic is an example of the highest level of computer programming sophistication available today, CADD interactive programming, for construction estimating The program runs on readily available hardware, is relatively easy to install and run, allows the estimator to do quantity take-off directly from computer drawings without sacrificing the ability to control estimate line item attribute such as unit cost, waste and productivity factors.

"The (construction) industry is on the verge of an order-of-magnitude improvement in efficiency and benefits resulting from the utilization of computerization" over the next three to five years with CADD Interactive Programs being a major contributor.[3] It is, therefore, imperative that we incorporate in the construction curricula adequate course work producing a graduate who is not only "computer literate" but has been properly exposed to representative estimating software from the four general categories discussed in this paper. Experience has shown that the construction student is very receptive, and even eager, to receive instruction on computer applications to construction estimating to and including the most CADD interactive programs.

A caveat must be underscored. We must not, in our enthusiasm for computer applications, forget to teach the student the basics of construction estimating. We must recognize the computer and its most impressive and intriguing applications is but a tool, albeit a very sophisticated one.

REFERENCES

TABLES

During the last half of 1989, questionnaires were mailed to 1,200 construction firms requesting data relative to the firm, along with concerning their computer software experiences and utilization. From the 424 responding firms, the following tabular data was assimilated: