+We use profiles to refer to accumulation of values along non-spatial axes.

+This can take the form of histograms, weighted averages, and the like. For

+instance, total mass as a function of Density, or the average Temperature as a

+A slice is an infinitesimally thin, variable resolution object that describes

+all the values at a given coordinate.

+\defslide{Cutting Plane}{

+Just like a slice, except not aligned with an axis. A lot slower, too.

+An on-axis traversal, such that each resultant point is composed of five

+elements: $(x, y, dx, dy, v)$, calculated such that $v_i = \int f(z) dl$, where

+$z$ is along the axis of integration and $dl$ is the local path length. They

+can also be calculated to return a weighted-average along sight lines. In

+\yt{} projections are variable resolution and must be ...

+The process of depositing values from a variable-resolution object (such as a

+projection or a slice) into a 2D buffer, from which an image can be made.

\defslide{Volume Rendering}{

+Usually ``volume rendering'' refers to some off-axis accumulation of colors

+along a plane of rays, for the purpose of visualization. In \yt{} we use it to

+refer to any traversal of the grid by a set of vectors, including off-axis

+projections, averages, calculations of covering fractions and so on. This

+includes as a side effect visualization!

+\bigsimple{Okay, that wraps up the intro.}