3D previs for virtual production.

What 3D previs settles that the other two cannot

Three approaches exist for seeing a film before the shoot, and the comparison page lays them side by side. The short version is that a drawn board settles intent, a generated frame settles the look, and a staged 3D scene settles the camera. The camera is the part a crew can build from, because once a scene is a space with dimensions the camera is no longer an adjective. It is a position, a height, a focal length and a target — four numbers — and four numbers can be repeated, reversed, handed to a grip and argued about precisely.

Virtual production makes this non-negotiable. On a volume the background is a screen, and the screen shows the right perspective only if the virtual camera and the physical camera agree about lens and position. On a location the sun is where it is at the call time and nowhere else. On a set piece with a crane, a vehicle or a stunt, the move has to be rigged before it can be shot, and a rig is built from numbers. In each case the question is not "does this look right" but "can this be made, and what does making it take" — and that question has only ever been answered by putting the camera in the world.

The workflow, step by step

Stage the set, do not model it. The traditional cost of 3D previs is the world: before a camera can be placed, someone has to build the room, rig the characters, dress the set. That fixed cost is paid whether the sequence is three shots or three hundred, and it is why small productions never reach for 3D at all. CineForge starts from a stage and a kit of ready-made stand-ins — figures, furniture, vehicles, architecture — placed at real size, so a chair is chair-sized and a doorway is a doorway. Block the scene in the time it takes to say it.

Forge what the kit lacks. A prop the scene needs and the kit does not have is described and forged as a clay stand-in, placed at the size you give it. It is a block with the right silhouette, honest about being a block; the real asset stays with the art department.

Place the camera as numbers. Position, height, lens and target, read off the control rather than guessed from a thumbnail. Dolly, orbit, change the lens, and watch the frame change the way the real one will. For a camera move, record it — with a mouse, or with a phone in your hand standing in for the camera body; the virtual camera on your phone page explains that pass.

Light it, and put the sun where it will be. A lighting rig with real materials so a note about the left-hand lamp is a change to a lamp. For an exterior, the sun at the location and the call time, so the question of whether the wide works at 4pm is answered on a Tuesday instead of at 4pm.

Then look, and then render. The staged scene is the ground truth; a render made from it inherits the camera and the locked cast, so the look is applied to a shot that already exists rather than invented alongside one. That is the order the workflow overview describes — the set before the picture.

Then techvis. From the settled camera, the physical answers: the track length, the crane height, the sun direction, the shot list with each camera's numbers. CineForge writes the techvis sheet from the set, and the shot list the set implies, so what leaves the room is what the grip and the first assistant director need rather than a picture of it.

What goes wrong

Building a world nobody needed. A week of modelling for a scene that could have been blocked with stand-ins in an hour. The fidelity of a previs scene should match the decision it is there to make; a blocking pass needs positions and sizes, not textures.

A camera that lies about its lens. A viewport with a field of view that no real lens has, so the frame on screen is not the frame the day gives. Insist on real focal lengths on a real sensor model, and check the numbers against the camera package before anyone trusts the picture.

Previs that never becomes techvis. A beautiful animated sequence that nobody turned into a track length or a sun angle, so the crew discovers the answers with a tape measure. If the output of the previs pass is only a video, the pass is half done.

Mistaking the stage for the build. A staged scene is a planning document. It is not a construction drawing, not a safety plan, and not a substitute for the specialist 3D department on a feature's hardest set piece. Knowing where the tool stops is part of using it well.

Where PREVIZ does it

CineForge is the room: a set staged in three dimensions with real materials and a lighting rig, a kit of stand-ins at real size, props forged from a description, the sun at a location and time, a camera whose position, height and lens are numbers, a recorded move, and a techvis sheet and shot list written from the set. The staged scene feeds Keyframe and Director, so the look and the motion are made on a shot that already has a camera; and the Continuity Lock holds the cast and the set across every render made from it. The rooms page describes CineForge beside the other five, and it is open on every plan, priced by credits.

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