Motion Blur
Blur fast-moving pixels along their path
Definition
Motion blur smears pixels along the direction of motion to mimic a camera shutter integrating light over a frame interval. Per-object motion blur uses motion vectors from the G-Buffer and gives the strongest cinematic feel; camera-only motion blur is cheaper but less convincing. It is almost always paired with TAA, which depends on the same motion vector buffer.
In production
Motion blur smears pixels along the direction of travel to mimic a real camera shutter integrating light over a frame's exposure time, and Unreal Engine 5 implements this per-object using motion vectors pulled from the same G-Buffer channel that TAA and DLSS/FSR read for reprojection. Per-object motion blur gives the strongest cinematic feel because a spinning wheel or swinging sword blurs independently of camera movement, while camera-only motion blur — cheaper to compute since it only needs camera velocity — is common on lower-end platforms where the full per-object pass isn't affordable. It is almost always paired with TAA and temporal upscalers, since disabling motion vectors for one system can inadvertently break TAA's reprojection on that same layer if not handled carefully. Racing games and shooters typically cap motion blur intensity or disable it entirely in competitive modes, since heavy blur on fast camera pans reduces target readability even though it improves the sense of speed in single-player campaigns.
