Parallel Direct Volume Rendering of Intersecting Curvilinear
and Unstructured Grids Using a Scan-line Algorithm and
K-D Trees
Scientific visualization of volume data is increasingly being used in applications such as
Medical Imaging and Computational Fluid Dynamics (CFD). Due to the irregular nature
of the geometry of CFD applications, volume data for CFD applications is often stored in
curvilinear or unstructured grids. This increases the computational and memory resources
needed to render the volume due to the limited amount of geometrical coherence that can
be exploited.
A method of rendering multiple, possibly intersecting, curvilinear and unstructured grids
is presented. This method, which has been implemented for a MIMD parallel architecture
is based on a scan-line algorithm and provides ray-cast quality images efficiently by taking
advantage of polygonal coherence between scan-lines. It is capable of rendering intersecting
grids without the computational and spatial expense of subdividing intersecting cells, which
most ray-casting and all cell projection methods must do. Further efficiency is obtained
by the use of a k-d tree with prefix-order partitioning of triangles, to reduce the number
of primitives that must be processed for one rendering. All rendering is done in software
which eliminates the need for specialized graphics hardware.
The performance and rendering quality of this algorithm are compared with hardware-
assisted cell projection algorithms, for both rectilinear and curvilinear grids, and with a
ray-casting algorithm for rectilinear grids.
My thesis (1.0 Mb pdf file)