A sparse voxel octree (SVO) is a 3D
computer graphics rendering technique using a
raycasting or sometimes a
ray tracing approach into an
octree
An octree is a tree data structure in which each internal node has exactly eight children. Octrees are most often used to partition a three-dimensional space by recursively subdividing it into eight octants. Octrees are the three-dimensional a ...
data representation.
The technique generally relies on generating and processing the hull of points (sparse
voxel
In 3D computer graphics, a voxel represents a value on a regular grid in three-dimensional space. As with pixels in a 2D bitmap, voxels themselves do not typically have their position (i.e. coordinates) explicitly encoded with their values. ...
s) which are visible, or may be visible, given the resolution and size of the screen.
There are two main advantages to the technique. The first is that only pixels that will be displayed are computed, with the screen resolution limiting the
level of detail required; this limits computational cost during rendering. The second is that interior voxels (those fully enclosed by other voxels) need not be included in the 3D data set; this limits the amount of 3D voxel data (and thus storage space) required for realistic, high-resolution digital models and/or environments.
The basic advantage of octrees is that, as a hierarchical
data structure
In computer science, a data structure is a data organization, management, and storage format that is usually chosen for Efficiency, efficient Data access, access to data. More precisely, a data structure is a collection of data values, the rel ...
, they need not be explored to their full depth. This means that a system can extract a small subset of voxels as they are needed. In addition, octrees permit smoothing of the underlying data, to help with
antialiasing.
It is, however, a generally less well developed technique than standard polygon-based
rasterisation
In computer graphics, rasterisation (British English) or rasterization (American English) is the task of taking an image described in a vector graphics format (shapes) and converting it into a raster image (a series of pixels, dots or lines, whic ...
schemes.
References
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3D computer graphics