Top-down refers to a mode of generation or processing in which the outcome is determined less by local interactions among lower-level elements and more by higher-level frameworks, externally supplied controls, or preset constraints. Pixel sorting is described as relatively top-down because pixels are rearranged according to upper-level processing conditions such as the processing range, direction, and sort key. Distortion is also considered top-down when it depends strongly on externally given coordinate control, including noise fields, masks, vector fields, control textures, and time functions.
The key point is that top-down does not simply mean “commanded from above.” Rather, it describes a structure in which the generative process depends on an already defined framework or mapping, instead of emerging primarily from the accumulation of local rules. Distortion can include bottom-up characteristics when it relies heavily on local reference to previous states or feedback. For this reason, top-down and bottom-up should be understood as tendencies along a spectrum rather than as strictly separate categories.