Video: Create Additional Mappings

Last updated 10 August 2026

A display arrives with one mapping, and it fills the display. A second mapping is how one physical screen serves content in more than one way: each video channel picks which mapping it renders through, so one channel can fill the screen while another lands in a corner of it.

Before you start

  • A display (or projection surface) in the scene

  • A clear idea of what the second mapping is for — its job is also its name

1. Open the display's mapping controls

Select the display in Scene Objects, then open Mapping in the Inspector. The existing mapping is listed, with a * marking it as the default.

2. Add the mapping

Below the list, pick the mapping type from the dropdown. For a flat screen choose Planar — the other types describe projection geometry a display does not have.

Click Create. The new mapping appears as a second row — then click its E button to edit it.

Each row carries the same four buttons: * makes it the default, E edits it, D duplicates it, - deletes it. The default mapping cannot be deleted.

3. Name it for its job

It arrives named after its type — Planar 2. Clear the Name field and describe what it does instead.

Months from now you will pick this from a dropdown in the Sequencer, where "Bottom left" beats "Planar 2".

4. Shape it

Adjust Mapping Position, Mapping Rotation and Mapping Size until the content sits where you want it. The Scene View updates as you drag.

For a rough size and position, drag the mapping's gizmo in the Scene View instead.

For exact placement, tick Pixel Values. The controls switch from metres to pixels: enter the screen's full resolution under Total Canvas Size, and the size of the region you want under Sub-Canvas Size.

Then move the region with Sub-Canvas Pos, which is its top-left corner in pixels.

Pixel Values only appears for a Planar mapping on a flat object — it is pixel arithmetic on a rectangle, so there is nothing for it to mean on a cylinder or a dome. Beside the size fields, Sub Aspect Ratio with its Set checkbox keeps width and height locked to a ratio while you type.

5. Apply it

Click Apply in the footer of the mapping editor. Cancel discards the edit, Reset returns the mapping to its starting state.

Apply is what commits the mapping. Saving the project does not apply an open edit for you — anything left unapplied is gone at the next Backstage restart.

6. Use it from a channel

In the Sequencer, select a video channel and open Destination in the Inspector.

Tick the display, then pick your new mapping from the dropdown beside it. The channel's track now names both — the display, and the mapping it renders through. Channels still on the default are unaffected.

Done when

The channel's track names the display and your new mapping, and its content sits in the region you shaped — while every other channel on that display is exactly where it was.

If the content did not move, the channel is still on the old mapping — adding a mapping changes nothing until a channel selects it. If every channel moved, you edited the default instead of the new one.

Adding a mapping is safe; changing which one is default is not. Pre-slicing in the Media Manager and Black Level Correction both use the default mapping to place their results, so re-pointing the * changes work that was already finished.

Shortcut. If the new mapping is a variation of an existing one, use that row's D button instead of Create — faster, and it leaves the original untouched. And although this video uses a Display, the process is identical on a projection surface, including one blended across several projectors.