Speed

Rendering speeds of a volume rendering system can vary with the volume being rendered, the transfer function being used, the viewing projection, and the image size. In this chapter, I give rendering times for several data sets taken from the NASA Advanced Supercomputing website¹¹and converted to tetrahedra. Table 1.1 lists the volumes used. Figure 1.1 shows sample renderings of the volumes.

Table 1.1: Data sets used for testing.

Data Set	Vertices	Tetrahedra
Blunt Fin	40,921	187,395
Oxygen Post	108,300	513,375
Delta Wing	211,680	1,005,675

(a) Blunt Fin	(b) Oxygen Post	(c) Delta Wing

The timings given in this section are for 800 by 800 pixel images unless otherwise specified. The transfer function used for each model is a fixed function with 8 to 10 control points. The renderings rotate the camera around the center of the model. The frame times given are an average of the rendering speed over every frame through the rotation. I performed the tests on a 3.2 GHz Pentium 4 with 2 GB of RAM and a Quadro FX 3000 graphics card. The Quadro graphics card has 256 MB of its own memory and resides on an AGP 8X bus.