EN Studio Assets

Assets and cutting

Français · Type: how-to · Audience: author · Context: local Studio · Status: ready · Applies from: 4.2.1

The local Studio · contract: stable · verified by CI (support matrix of 4.4.0, 2026-10-23): Chromium end to end (the Studio's checks); Windows: the unit suite only · automated checks: jobs e2e, windows; CI plan e2e, windows; 2 test files · people's passes: studio-hero-matrix not run (#238) · known limits: demo-read-only

The Assets tab lists every image and sound of the game against what the game uses, gives each sheet its art prompt, and takes the generated images and sounds that replace or add to them, cutting sheets into cells, without ever deleting a file.

What you get

A generated sprite sheet cut into the cells the game names, a picture or a sound replaced with the old one kept beside it, and the game showing the new art once prepared.

Context and versions

The local Studio, in the engine repository or a created project. True from 4.2.1 (every upload is one operation of the game's journal). The demo Studio shows the listing read-only; a hosted Studio has the same tab with its own limits (below).

Prerequisites

• The Studio running (overview).
• Python 3 with Pillow for cutting and keying (tools/cut-sheet.py), ffmpeg for sounds, the image and audio toolchains: Image toolchain, Audio toolchain.
• The art prompts and the sheet ids come from the game: Images: prompts, cutting sheets, transparency, scale.

Where to run the commands

In the browser, on the Assets tab. Prepare assets runs npm run assets for you, in the folder the Studio serves.

The Assets tab

The tab lists everything under games/<id>/art/ and audio/ against what the game references (tools/refs.ts), with the prompts of npm run prompts (tools/prompts.ts).

• Tree (left): Characters (one entry per sprite sheet, named after the character whose poses it holds), Objects, Backgrounds, Furniture, Talk kits, Sounds (music, sound effects). Badges: red = cells the game references without a file; orange = used but not prepared, or older than their source; grey = cut but unused.
• Sheet (centre): the cells as thumbnails with their id and what uses them (walk, portrait, items.key, house.props.pantry…); filters All / Used / Unused / Missing. On top, the Prompt panel: the sheet's section of the prompts with Copy prompt (the fenced block for the image model), Copy prompt for missing cells only when some are missing, and the shared Style block (folded) with its own Copy.
• Cell (right): large preview, file, size, image ids, prepared or not, where it is used (with "Open room"), Replace…, and the backups.
• Backgrounds: the decor with the room's hotspots, props (foot and height), actors and walk area drawn over it, and the dashed floor band the prompt asks to keep empty; Replace… and "+ background".
• Sounds: a player per file, where it is used, Replace… (same extension) and Add sound…. The music and sound ids the game declares are listed whether or not a file exists; npm run assets ships what is there and reports what is missing (Music).

Steps

1. Pick the sheet in the tree, Copy prompt (or Copy prompt for missing cells only) and generate the image with your image model.

2. Upload generated sheet… sends the image with the sheet's id and grid (6 × 4 by default). It is saved under private/sheets/<sheetId>-<time>.<ext> and cut by tools/cut-sheet.py into art/<sheetId>/. If cells of that sheet exist already, a dialog lists them, each with a recut box: unticked, the cell is kept and only the new cells are cut. The cut result is shown. For a sheet that has no folder yet, use Upload sheet into a new sheet id… in the toolbar.

3. To change one picture, select the cell and Replace…. Keying: a flat background is keyed by default; choose "always" or "never" to force it. A decor (PNG or JPEG) is replaced the same way from Backgrounds, a sound from Sounds (any format ffmpeg reads, same extension).

4. Prepare assets (npm run assets) in the toolbar runs the pipeline with its output live in a drawer; the count next to it is what it would process. Afterwards the Rooms view reloads. A replaced cell shows in the game once prepared.

Guarantee · no-silent-recut · referenced · scope self-checked by the author (AI), not reviewed An upload that would recut existing cells without naming them is refused with 409 and the list of those cells. An upload that names a cell recuts only that cell, and the old file is kept as <name>_v<N> first.

Nothing is deleted: a replaced sound or decor is kept as <name>_v<N> too.

Backups are not cells: the listing and the prompts ignore them.

Limit · demo-read-only In the demo Studio the listing comes from the snapshot (assets in snapshot.json), the thumbnails and sounds from the prepared files of public/assets (unused cells have no preview); uploads and Prepare are hidden.

On a hosted Studio

Applies from 4.2.3

The same tab, served by the Studio Server under /api/assets. Uploads are bounded (10 MiB; PNG, JPEG or WebP images, Ogg, MP3 or WAV sounds, recognised from their bytes); the cutting, the keying and Prepare assets (on the server) are jobs of the processing worker, under the project's exclusive lease, shown in a small panel with a Cancel button (a job cancelled before its write leaves nothing). The uploaded sheet itself is not kept there. See Hosted assets.

Expected result, and how to check it

The cell's badge leaves red; after Prepare it leaves orange; the cell shows in the game. git status shows the new files under art/<sheetId>/ and the _v<N> backups beside them.

Common errors

Symptom	Cause	Fix
409 with conflicts on an upload	Cells of that sheet exist and were not named	Tick recut for the cells to replace, or leave them kept
`sheetId` must be letters, digits, _ and - (not "decor")	A bad sheet id	Use the game's sheet id
A replaced cell does not show in the game	Not prepared yet (orange badge)	Prepare assets
The cut fails	Python 3 or Pillow is missing	Image toolchain

Files or data changed

games/<id>/art/<sheetId>/<cell>.png and their _v<N> backups; art/decor/<name>.<ext>; audio/<music|sfx>/<file>; the uploaded sheet under games/<id>/private/sheets/; the prepared files under public/assets/ after Prepare.

Recovery or going back

A replaced file is kept as <name>_v<N>: copy it back over the cell, or use git. Prepare can be run again at any time.

References

• Server side: tools/studio/assets.ts (mounted at /__studio/api/assets), the cutting in tools/studio/cut.ts. The tab: src/studio/assets.ts with its model, IO and views beside it (assets-model.ts, assets-io.ts, assets-view.ts, assets-sheets.ts, assets-decors.ts, assets-sounds.ts); the Storyboard and Rooms tabs are laid out the same way since 4.1.8, every file under 800 lines.
• The routes: Studio API.

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