Content Packs

Content Packs

A content pack is a ZIP of plain files that the Asset Store installs. Packs are layer L2 (see Feature Layers): they carry content, never code, and nothing in a pack runs when you install it. Every file is hash-checked, and UO's own data files are refused.

GUO never ships UO art. A pack carries art its author made and holds the rights to, with its licence in the manifest.

What packs can carry today

Pack content	What it does in the game	Switched on by
Backgrounds, themes, sounds, profile presets	The canvas behind the game, the screen saver, login and UI looks	Choosing them in Options
Screen effects	Extra looks for the screen effect menu	Choosing a look; installing selects nothing, and Classic switches effects off. See Screen Effects
HD art (hd-art)	Larger, more detailed drawings of world tiles	Options > Enhanced HD (installed packs), off by default
Regional music and sounds	Music and ambient sound by area of the map	Options > Sound > Regional audio and recorded NPC voices, off by default
Recorded voices (voice)	Recorded speech for an NPC, matched by name, then by body	The same Sound option
3D splats (splat)	A 3D stand-in for one static	Installs, but the game does not show them yet
Art, gumps, hues, fonts, map blocks, tile data, animations, translations	Content added on top of your install, bound to explicit IDs	Selecting a deployment in the Store's Configure deployment window; restart to apply

Enhanced HD

With the option on, world sprites use the PNG from an installed HD art pack. Anything the pack does not cover, and any drawing whose size does not match your own install, stays native art. The mouse cursor, the backpack, clicking and shadows always use native art. The filter is a profile choice: Auto (sharp when the HD scale equals your zoom), Point, Point with mipmaps or Smooth. With the option off, the game draws exactly as before; the proof compares every pixel. ADR-0027.

Measured so far on a synthetic pack at the Britain bank: fewer texture switches per frame, but no CPU gain, so the option stays off by default until a dense town is measured.

Regional audio and recorded voices

With the option on, an installed region can play its own music and sounds, and an NPC whose name (or body) a voice pack covers speaks its recorded lines. A line with no recording stays silent. NPC speech no longer uses text-to-speech: a voice you set up before October 2026 is silent until a recorded voice pack covers that NPC. Recordings are WAV, PCM 22050 Hz mono 16-bit. ADR-0036.

The scripted checks prove the packs are read and matched; hearing a live NPC speak through one is written, not verified.

Making a pack

• The pack format is docs/data_formats.md section 12 and, for the newer content kinds, docs/asset_pack_ecosystem.md.
• python tools\asset_store\content_examples.py --out <folder> writes editable example packs and their ZIPs.
• The screen effect pack's source is design/packs/jarjar-postfx/, a worked example of a pack built from a folder.
• Generating content (HD upscales, voices) belongs in the editor or Labs, never in the game client.

Not yet

• A server telling your client which packs it needs (shard content negotiation) is on the Roadmap; nothing downloads or switches on by itself.
• Showing 3D splats in the world.
• A public hosted catalogue; today a store is a folder you serve yourself.