A Response to “Building 3D Worlds – 3D Geometric Graphics I” by Anne Spalter and “Geometric Modeling” by Yehuda Kalay
The argument for complexity within digital representation is supported through Kalay’s article,“ Geometric Modeling” as real-life objects within their realistic settings are described as “a well informed balance of various attributes including generality, efficiency, and completeness” (Kalay pg. 141). Additionally, the introduction of wire-frame, surface, and solid modeling provides a basis for further discussion of the various approaches to the completion of 3D modeling techniques.
While the approach to modeling through wire frame is classified as the most simplistic and dated form of graphical computation, it still requires the inferring of the viewer who is typically trained to comprehend the visual representation of data (Kalay pg.141-142). However, due to the lack of ‘completeness’ found within this modeling technique the ability to fully discern the relationship amongst various objects in wire-frame construction is greatly compromised even for those trained to view through an interring lens (Kalay pg.142). In contrast, surface modeling provides a clearer view of the visual relationship formed through the connection of multiple objects, yet it still lacks a definite reading of adjacencies, surface area, and volume amongst various objects (Kalay pg. 142 -143). Therefore, solid modeling offers the greatest level of completeness in the readability and discernment of a model and becomes the closest digital representation of the physical model that allows the support of Boolean operations (including: union, intersection, and subtraction). These approaches for completing solid forms are described as spatial occupancy enumeration, constructive solid geometry (CSG) and boundary representation (B-rep) and are completed through various techniques. While spatial occupancy enumeration is accomplished through a grid (spatial array) and cells that are assigned to the object and provides an accurate calculation of volume, it lacks a clear view of relationship between cells since these cells are essentially grouped together as belonging to one particular object (Kalay pg.143 -144). Constructive Solid Geometry is also achieved through the combination of simplistic objects to re-create another form or object yet, the efficiency in this modeling technique occurs as Boolean operations (i.e. union) are simply recorded on the surfaces and structural data of primitive objects (Kalay pg. 144-45). Furthermore, Boundary Representation differs from both SOE and CSG due to the fact that it’s representation of exclusive points within a boundary includes a specific arrangement of vertices, edges, and faces. The accuracy of Boundary Representation is restricted to obtaining a non-self penetrating bounding surface in order to provide a concise representation. As a result, B-rep modeling combines both surface and volumetric modeling, while providing optimal surface visualization of the model (Kalay pg.146).
Spalter’s article, “Building 3D Worlds – 3D Geometric Graphics I” provides a valuable discourse regarding the usage and adaptability of 3-D modeling software. ‘Scientific Visualization’, described as a representative image based on the collection of data essentially, provides the allowance for modeling of the 3D world as it relates to an object, light interaction, as well as behavioral attributes (pg.216). These allowances are created through the performance of duties described as: the creation of basic elements of an object, the assembly, the arrangement of scenery, selection of materials and lighting, and selection of viewpoints and rendering attributes. Additionally, the dependency of medical research creates an additional avenue for both the realistic modeling of volume visualization (modeling of object’s interiors) and volumetric sculpting (sculpting of voxel-based models) while providing a venue for 3D painting to further formulate (pg. 218). In regards to the realistic demands of digital modeling, the methods of digital clay and 3D sculpting can also incorporate spline patches that create linear contours in complex forms. Coupled with realistic modeling curves and NURBS-based modeling, spline modeling provides one of the most accurate forms of pre-planned detailing and editing (pg. 228-29).
The planned acuteness of digital modeling is critical to the completeness of 3D representation. For example the moving of vertices within an object will create a non-symmetrical shape that is well adaptable to future sculpting. Yet in contrast, the rotation of a 2D profile will create a symmetrical object that also is available for future editing of the final object, but does not provide the same editing abilities of the original attributes found in lofted modeling (Spalter pg.230). Respectively, the planning of final appearance, editing, and hierarchy prove to be critical components of holistic 3D modeling.
Kalay’s and Spalter’s articles provide a basis for determining which initial modeling techniques are most appropriate for modeling both objects and buildings. The degree of visualization required by the viewer and the expectation of future manipulation can greatly influence the modeling of an interior object and a building’s interior and exterior components (Kalay 2004.) Essentially, the various techniques of digital modeling create a new tool palette for architects and designers that enhance the informative efficiencies of modeling.
While there are great efficiencies to be gained through 3D modeling, the effectiveness of 3D modeling can become diluted if the attributes of physical modeling are re-missed. Since there is little room for exploration during the 3D modeling phase, physical modeling still creates a viable venue for the exploration of ideals, concepts, and even materials. In retrospect, the danger of deficient exploratory process can also be alleviated through programs such as Sketch (produced by Robert Zeleznik), which provides a medium between hand sketches and computer-based modeling software (Spalter pg. 232-33). Thus, the manipulation of future digital modeling techniques creates an opportunity for the improvement of concise modeling and readability within digital conceptualization (Kalay 2004). As technology becomes more readily available architects, designers, and artists will obtain more efficient and accurate means to develop meaningful and holistic 3D models.
– Kimberlie M. Wade
Articles:
Kalay, Y. (2004). Geometric Modeling. In Modeling – Architecture’s New Media (pp. 141-147). The MIT Press.

Spalter, A. (1999). Building 3D Worlds – 3D Geometric Graphics I. The Computer in the Visual Arts (pp. 212-253). Addison Wesley Longman Inc.