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Software Description

The BDA is a computer program that supports the concurrent, integrated use of multiple simulation tools and databases, through a single, object-based representation of building components and systems. Based on a comprehensive design theory, the BDA acts as a data manager and process controller, allowing building designers to benefit from the capabilities of multiple analysis and visualization tools throughout the building design process. The BDA has a simple Graphical User Interface that is based on two main elements, the Building Browser and the Decision Desktop.

The BDA is linked to a Schematic Graphic Editor that allows designers to quickly and easily specify basic building geometric parameters. Through a Default Value Selector, the BDA automatically assigns "smart" default values to all non-geometric parameters required by the analysis tools from a Prototypes Database. These default values can be easily reviewed and changed through the Building Browser. In this way BDA supports the use of sophisticated tools from the initial, schematic phases of building design.

The BDA is implemented as a Windows™-based application for personal computers. In addition to the Schematic Graphic Editor, the current version of the BDA is linked to DCM (daylighting computation module), ECM (Electric lighting computation module) and DOE-2 (energy analysis module). The current version also provides the choice of using either the English or the Metric unit system. Future versions of BDA will be linked to additional analysis and visualization tools, such as Radiance (day/lighting and rendering) and ATHENA (lifecycle cost of materials). Plans for the future also include links to cost estimating modules, building rating systems, CAD software and electronic product catalogs.

Building Browser

The Building Browser allows building designers to quickly navigate through the multitude of descriptive and performance parameters addressed by the analysis and visualization tools linked to BDA. Through the Building Browser the user can edit the values of input objects and parameters and select any number of input and output parameters to display in the Decision Desktop.
browser.gif (28436 bytes) Building Browser Screen-dump.

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Decision Desktop

The Decision Desktop allows building designers to compare multiple alternative design solutions with respect to multiple design considerations, as addressed by the analysis and visualization tools and databases linked to the BDA. The parameters displayed in the Decision Desktop are selected in the Building Browser. The Decision Desktop supports a large variety of data types, including 2-D and 3-D distributions, images, sound and video, which can be displayed and edited in their own windows.
desktop.gif (36218 bytes) Decision Desktop Screen-dump

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Schematic Graphic Editor

The Schematic Graphic Editor (SGE) is a stand-alone application developed specifically for use with the BDA software. SGE is a graphic editor for the initial, schematic phases of building design. SGE supports the drawing of building components and systems, such as spaces, windows, doors, etc., while it continuously communicates with the BDA for the population of the building model with appropriate building objects, such as walls, floors, ceilings, constructions, schedules, etc. The values of the non-geometric characteristics of these building objects are initially defaulted through the Default Value Selector (DVS). The user can change these default values at any point through the BDA user interface.
sge.gif (21825 bytes) Schematic Graphic Editor Screen-dump

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Default Value Selector

The Default Value Selector (DVS) is a mechanism for the automatic assignment of default values for all parameters that have not been addressed by the user and are required as input by the simulation tools linked to the BDA. The DVS is an integral part of the BDA and works in synch with the Schematic Graphic Editor (SGE).

As the SGE sends information to the BDA about each object that the user draws on the screen, the DVS selects default values from the Prototypes Database, based on building location and type, and in some cases space type and boundary type. The rules for the selection of the default values follows building codes, standards, and recommended practice, taken from a number of sources, such as the ASHRAE Handbook of Fundamentals, the Handbook of the Illuminating Engineering Society, etc. The user can change the default values at any point through the BDA user interface.

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Prototypes Database

The Prototypes Database is used to store Libraries of predefined building objects, or Prototypes, e.g., glazings, wall constructions, etc. Each Prototype is created with its own list of parameters as defined in the Schema Database, and each parameter is assigned a Value from some Source or Data Reference. The Prototypes Database is the main source of building components and systems available to the user for the description of the building.

Like the Schema Database, the Prototypes Database has its own Graphical User Interface that allows developers to enter new Prototypes and modify existing ones. Moreover, it too has reporting utilities that allow listing of all Instances for each Object Type, so that all of the Prototypical Database contents we be listed and printed.

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The Schema Database

The Schema Database describes the content, or structure, of items that BDA can store. These items are Building Objects (e.g. space, wall), Relations used to link objects together (e.g., has, faces), Properties that describe the objects (e.g., height, U-value), Units used to measure properties (e.g., ft., cm., C, F), and Simulation Tools that compute values of performance properties (e.g. DOE-2, RADIANCE, etc.). Each object parameter is linked to the simulation tools that use it as input or output along with the associated type of units.

To facilitate the development of the Schema Database we developed a Graphical User Interface that allows developers to define new Simulation Tools, Building Object, Properties, Units, and Relations. The Schema Database also has reporting utilities that allow developers to check the consistency and semantics of the Schema (e.g. parameter definitions and relations to simulation tools).

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Copyright 1997 The Regents of the University of California.
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Last updated: November 02, 2006.