Most of the visualization techniques in EnSight use points, lines, and surfaces to represent data, requiring volumetric data to be subsampled in some way. Volume rendering is a visualization technique that allows the user to view an entire volume of data at once, without having to slice the data in any way. The process involves finding all cells that overlap each pixel and accumulating a color for that pixel from the color and transparency of each cell. Volumes can be constant colored, but more often you will color the volume using a palette corresponding to a variable or a variable component. Color palettes include transparency (alpha) values, allowing control of transparency based on variable value.