BIM Resources @ Georgia Tech

Taxonomy section describes the meaning and context of each word used in the BIM Resources @ GeorgiaTech. This taxonomy aims to clearly describe the specification, functaionality and exchange capabilities of BIM tools. The definition may conflict with general definition of the taxonomy, though the BIM Resources @ GeorgiaTech tries to convey the general definition.
Geometry Modeling Tools	Software capable of creating 3D geometric object.
Preliminary architectural design Tools	Software capable of creating architectural object in 3D.
Architectural design Tools	Software capable of creating geometric object with associated information. The associated information should be able to represent object types, especially AEC object, such as wall, door, etc.
Structural Design Tools	Software capable of creating structural 3D model for a building.
Structural Analysis Tools	Software capable of analyzing structural performance of a building.

Construction Tools	Software capable of creating object with construction information.
Fabrication Tools	Software capable of creating CAM data out of 3D model.
Object(s)	Objects are the internal representation of real world items or concepts in the discourse of the application domain. In BIM, objects could be recognized as building elements for instance a piece of geometry, a solid primitive, a beam, a column, a window, a staircase, etc. An object can also be assembled and represented by multiple objects. At the implementation level, an object usually can be instantiated through a class that constructs the particular object. There are two types of objects 1) Predefined objects and 2) User definable objects
Predefined Object	A predefined object is an object that can be only instantiated internally by the application. A predefined object can be assembled by many objects. Properties of a predefined object are not totally accessible by users through the 1) UI (User Interface); or the 2) API (Application Programming Interface) or SDK (Software Development Tools) of an application. Parametric behavior of a predefined object is usually static where limited constraints and variables are publicly accessible to users.
User Definable Object	User definable objects is where users can build an object from scratch and have full control on the design of an object in terms of 1) the geometric representation; 2) properties; 3) constraints and variables for its parametric behavior. At the implementation level, a user definable object is usually constructed and inherent from a class of a predefined object, allowing user to associate additional properties to a specialized object. Such a user definable object is therefore reusable through the UI or API/SDK. Users are allowed to create, remove or modify constraints and variables at all parametric levels.
Parameter	variables used in an equation to assign values : coordinate, dimension, material, distance, angle, color, unit price, energy coefficient, ...
Geometric Parameter	One type of parameter especially used to define the intrinsic properties of geometry, for example, coordinate, surface parameters, and angle. Also measurements of a shape: distance, area, volume, and centroid.
Constraint	Generally, combinational Boolean limits in a parameter and among parameters, for instance, inequality( >, < ) and equality( = ).
Geometric constraints	one type of constraint especially limits mathematical relationships between geometric parameters. For instance, a dimension can be constrained by fixed length or by range, and the parallel of two lines is a geometric constraint which limits the angles of two lines to be equal.
Parametric behavior	the reaction of parameters or variables by changing of a parameter according to the defined relations and constraints among the parameters.
Parametric shape	(= Dimension-driven creation and modification of building components) A type of shape, which is defined to have parametric behavior (= parametric control). In order to have parametric behavior, all geometric elements of the shape should be related and constrained to each others.
Parametric curved surfaces	(a type of parametric shape): A type of surface model, defined to have parametric behavior. For instance, Bezier, spline, b-spline, and Nurbs surface are all parametric curved surface, because the surfaces can be controlled by control points.
Parametric solid	(a type of parametric shape): a solid model defined to have parametric behavior. In order to have parametric behavior, all geometric elements of the solid should be related and constrained to each others.