Hvad er USD-filformatet?
En .usd-fil gemmer en 3D-scene i Pixars Universal Scene Description-format, det open-source framework som Pixar udgav i juli 2016, og som nu vedligeholdes som OpenUSD under Academy Software Foundation. Filen indeholder geometri, skyggedata og referencer til andre aktiver, alt sammen organiseret som et hierarki af «prims», som USD sammensætter til en enkelt scenegraf.
Filtypen .usd er bevidst format-agnostisk. En fil kan indeholde enten læsbar UTF-8-tekst, den samme grammatik som bruges af .usda, eller den binære Crate-kodning, der bruges af .usdc. USD læser header-bytes for at beslutte: en Crate-nyttelast begynder med ASCII-strengen PXR-USDC, mens en tekst-nyttelast begynder med #usda 1.0. Dette lader et studie udskifte et tekstlag med et binært uden at omdøbe filen eller ødelægge referencer, der peger på den.
Det, der gør USD unik, er ikke-destruktiv sammensætning (composition). Underlag, referencer, nyttelaster og varianter samler mange filer til én «stage» uden at ændre kildedataene, hvilket er grunden til, at formatet forankrer pipelines hos Pixar, i NVIDIA Omniverse og i Apples AR-værktøjer.
Sikkerhed og tryghed
RISIKO: LOWA .usd file is scene-description data, not an executable, so opening one does not run code by itself. The main caution is that USD layers can reference or sublayer external files and payloads by path, and some pipelines allow plugin-based procedurals, so only load .usd assets from sources you trust. The binary Crate variant is memory-mapped, which is fast but means malformed files should be opened in an up-to-date reader.
Formatdetaljer
kort fortalt- US Dollar amount export - Some finance and accounting exports use .usd as a currency label, but this is an uncommon, non-standard use unrelated to 3D scenes.
- UltraSonic Data / instrument logs - A few ultrasonic testing and lab instruments write proprietary .usd data logs; these are vendor-specific and unrelated to Pixar USD.
Programmer der åbner USD-filer
Windows5 apps
Blender
Open-source Use File > Import > Universal Scene Description to bring the .usd scene into Blender. 
Autodesk Maya
Betalt Import or reference a .usd file through the built-in USD plugin to edit geometry and shading. 
OpenUSD (usdview / usdcat)
Open-source Install the OpenUSD toolset and run usdview scene.usd to inspect and play back the scene, or usdcat scene.usd to dump its contents.
SideFX Houdini
Freemium Load the .usd layer into the Solaris/LOP context to build, layout, and render the scene.
NVIDIA Omniverse
Freemium Open the .usd stage in USD Composer/View to collaborate on and render the scene. 
macOS5 apps
OpenUSD (usdview / usdcat)
Open-source Build or install OpenUSD and run usdview scene.usd to view the scene or usdcat to convert and inspect it. 
Linux4 apps
OpenUSD (usdview / usdcat)
Open-source Run usdview scene.usd from the OpenUSD build to inspect and play the scene, or usdcat to read and convert it.
SideFX Houdini
Freemium Load the .usd layer in the Solaris/LOP context for scene assembly and rendering. Tekniske detaljer
dyb specifikation| Encoding | Dual: UTF-8 plain text (ASCII/usda payload) or binary Crate (usdc payload) inside the same .usd extension |
| Byte order | Little-endian for the binary Crate payload |
| Container | Layer file that composes a scenegraph; can reference and sublayer other USD layers and external assets |
| Compression | None for the ASCII payload; the Crate binary payload uses internal compression and memory-mappable, random-access sections optimized for fast lookup |
| Typical size | Kilobytes for small stubs and reference layers up to gigabytes for full production scenes |
| Structure | USD stores a hierarchy of prims (primitives) carrying typed attributes and relationships. Composition arcs (sublayers, references, payloads, variants, inherits, specializes) let many layers be assembled non-destructively into one composed stage. The plain .usd extension defers to either the usda text grammar or the usdc Crate encoding, selected at runtime from the file header. |
| Integrity | No built-in checksum; the Crate format relies on structural offsets and a version field in its header |
| Platforms | Windows, macOS, Linux |
| Notes | The .usd extension is deliberately format-agnostic: teams can swap a text layer for a binary Crate layer without renaming the file or breaking references. The USD_DEFAULT_FILE_FORMAT environment variable controls which encoding a new .usd file gets (Crate by default). Conversion in either direction is done with the usdcat tool. |
| Structure Type | Scenegraph / layered composition |
| Udgivet | 2016 (open-sourced July 26, 2016; developed at Pixar since ~2012) |
| Seneste version | OpenUSD 26.08 (2026) |
| Åben standard | Ja · royaltyfri |
| Specifikation | openusd.org |
USD-konverteringer
Fællesskabets Q&A
spurgt af brugereIngen spørgsmål endnu - vær den første til at spørge om USD-filer.
Ofte stillede spørgsmål
Hvordan åbner jeg en .usd-fil?
usdview som en gratis viewer, eller åbn den i Autodesk Maya, SideFX Houdini, Blender eller NVIDIA Omniverse. Blenders File > Import > Universal Scene Description er den hurtigste gratis vej for de fleste kunstnere.Er en .usd-fil tekst eller binær?
.usd-filtype er en container, der enten indeholder ASCII-tekst (som .usda) eller den binære Crate-kodning (som .usdc). USD-værktøjer læser filens header for at beslutte, hvilken parser der skal bruges.Hvad er forskellen på .usd, .usda, .usdc og .usdz?
.usda er altid ASCII-tekst, .usdc er altid binær Crate, og .usd kan være begge dele. .usdz er en zippet, skrivebeskyttet pakke, der samler en scene med dens teksturer til distribution og AR.Kan jeg redigere en .usd-fil i en teksteditor?
usdcat scene.usd --out scene.usda --usdFormat usda, rediger teksten, og konverter derefter tilbage om nødvendigt.Er USD gratis at bruge?
Hvordan laver jeg en .usd om til en .usdz til AR?
usdzip scene.usd -o scene.usdz, eller eksporter direkte fra Houdini, Maya eller Omniverse. Det resulterende .usdz er det format, Apples AR Quick Look forventer.
