A 3-dimensional representation for fast rendering of complex scenes

Abstract

Hierarchical representationsof 3-dimensional objects are both time and space efficient. They typically consist of trees whose branches represent bounding volumes and whose terminal nodes represent primitive object elements (usually polygons).This paper describes a method whereby the object space is represented entirely by a hierarchical data structure consisting of bounding volumes, with no other form of representation. This homogeneity allows the visible surface rendering to be performed simply and efficiently.The bounding volumes selected for this algorithm are parallelepipeds oriented to minimize their size. With this representation, any surface can be rendered since in the limit the bounding volumes make up a point representation of the object. The advantage is that the visibility calculations consist only of a search through the data structure to determine the correspondence between terminal level bounding volumes and the current pixel. For ray tracing algorithms, this means that a simplified operation will produce the point of intersection of each ray with the bounding volumes.Memory requirements are minimized by expanding or fetching the lower levels of the hierarchy only when required. Because the viewing process has a single operation and primitive type, the software or hardware chosen to implement the search can be highly optimized for very fast execution.

Computer Generated Holograms of 3D Points Cloud

“…For testing purposes six 3D models [15,16] were made with different complexity levels, which is reflected in the different number of points (1, 10, 100, 1000, 10000 and 100000 points) (Fig. 4).…”

Multiprocessing for ray tracing: a hierarchical self-balancing approach

“…For each ray, its closest intersected object is found by traversing the hierarchical tree, starting at its root and towards its leaves. The method was first introduced by Rubin and Whitted (1980), and was improved by Weghorst et al (1984), and made even faster by Kay and Kajiya (1986). The first step in the algorithm is building the data structure.…”

“…The building of the data structure is not a trivial task. Rubin and Whitted designed an interactive program, and it took them about two days to build a hierarchical tree for a complex scene, Rubin and Whitted (1980). In Kay (1986) the desired features of a "good" hierarchy are described.…”

Experimental CSG environment for modelling solid

“…Since KIT handles a wide range of primitives, rendering method must be independent from data structure such as in ray tracing. One of the most important drawbacks of ray tracing is that it is slow, but several researches have done to improve its speed (Dippe and Swensen 1984;Bronsvoort et al 1984;Glassner 1984; Rubin and Whitted 1980;Weghorst et al 1984). The KIT ray tracer uses an hierarchical enclosure based on extended-CSG structure for this purpose.…”