Domain Clipping, Region-of-interest (ROI)
This is very similar to slice planes in look and technical implementation, We imagine cutting away a portion of the domain, or alternatively cropping the domain. When a visualization is limited to a piece of the original domain, this sub-domain is often called the “region of interest” (ROI).
Clipping out a “brick”:
Clipping out a portion of a sphere (you can think of the sphere as a cutting tool).