Previz, short for previsualization, is a rough moving version of a sequence made before production to test staging, camera movement, and timing while changes are still cheap.
A storyboard shows you the shots. Previz shows you whether they cut together. That distinction sounds academic until a sequence that read perfectly as twelve frames turns out to have no time to breathe once the frames have durations.
How it works
Previz sits between the storyboard and the shoot. The traditional version is animated in 3D at low fidelity: grey geometry, blocked camera moves, real durations, no lighting or texture. Feature films and commercials with complex staging have used it for years, and the reason it stayed a big-budget tool is that it required a 3D artist and a schedule.
The AI-era version is different in method and identical in purpose. Instead of blocking cameras in 3D, you generate short clips for each beat and assemble them at real durations. The output looks nothing like previz traditionally did (it looks like footage rather than grey blocks) and it answers the same questions: does the sequence read, does the pacing work, does that camera move belong.
The cost moved accordingly. Using canon 8frame prices, a six-beat sequence generated on Veo 3.1 Lite at 54 credits per 8-second clip with audio is 324 credits, about $3.24 at pack rate, inside a $19 Starter month with room to redo it twice.
What previz answers
Timing. Whether the beats fit the runtime, which is the question a static board cannot answer.
Continuity of movement. Whether a push-in followed by a whip pan is energy or nausea.
Coverage gaps. The cutaway you did not plan and will need.
Client comprehension. Some clients cannot read a storyboard. Almost everyone can read moving pictures.
Previz vs animatic vs storyboard
A storyboard is stills. An animatic is those stills cut to time, often with scratch audio. Previz is moving images at rough fidelity. The three form a ladder of cost and certainty, and most ad productions stop at the animatic unless staging is genuinely complex.
Examples
A car commercial. Six generated beats at real durations reveal that the hero reveal lands four seconds too late, which is a rewrite on a canvas and a reshoot on a location day.
A product demo. Three beats confirm the hand-to-product handoff reads at 2 seconds, so the shoot does not need the extra coverage originally scheduled.
Related concepts
What is an animatic covers the cut-to-time stills version. What is a shot list is the document previz tests. AI previsualization for agencies covers the agency workflow in depth.
Previz earns its keep when generating a beat costs less than debating it. The 8frame canvas is free and unlimited, and generation is paid from $19/month.