What is the PRW file format?
.prw files are shader preview thumbnails used by the Artlantis architectural rendering software, developed by Abvent and continued as Artlantis RT² by Studio Base 2. Each .prw file stores a small rendered preview image of an Artlantis shader or material, displayed as a swatch in the application's shader library browser.
The format is proprietary and binary; the embedded preview is likely JPEG-compressed at approximately 128×128 to 256×256 pixels, with a color depth of 24-bit RGB or 32-bit RGBA. Typical file sizes fall between 10 KB and 500 KB. No public specification or magic byte signature is documented.
.prw files are not standalone viewable images and cannot be meaningfully opened outside Artlantis. They appear alongside .atl or .aof shader files in Artlantis material library directories. Abvent R&D closed and distribution of classic Artlantis ceased. The successor product, Artlantis RT² (July 2023, Studio Base 2), uses a new shader system; compatibility with .prw files from pre-RT² Artlantis (versions 2-2021) is unclear. ArchiCAD users frequently encounter .prw files due to the historical ArchiCAD-Artlantis shader library integration.
Security & safety
RISK: LOWPRW is a passive proprietary preview/thumbnail file with no known execution capability. Low risk - the main concern is downloading shader packs from unofficial sites, which could bundle malicious files alongside legitimate .prw content.
Format details
in a nutshellPrograms that open PRW files
Windows2 apps
ArchiCAD
Paid ArchiCAD's Artlantis rendering connection can display Artlantis shader previews within the workflow. 
Artlantis (classic, v2-2021)
Paid PRW files render automatically in Artlantis's shader browser when shader packs are installed. No manual open action - displayed as thumbnails only. 
macOS2 apps
Artlantis (classic, v2-2021)
Paid Same as Windows - PRW displays automatically in the shader browser. Technical details
deep spec| Encoding | Binary (proprietary Artlantis shader container) |
| Byte order | Likely little-endian (Windows-originated format, also used on macOS) |
| Preview image encoding | Likely JPEG-compressed image embedded within the proprietary container |
| Color depth | 24-bit RGB or 32-bit RGBA (preview thumbnail component) |
| Typical thumbnail dimensions | Approximately 128×128 to 256×256 pixels (undocumented; approximate) |
| Typical file size | 10 KB - 500 KB |
| Platform | Windows and macOS (Artlantis was cross-platform) |
| Role in application | Material/shader library swatch in Artlantis shader browser - not a standalone image file |
| Version scope | Artlantis versions 2 through 2021 (pre-RT²); Artlantis RT² (2023) uses a new shader system |
| Related formats | .atl (Artlantis scene file), .aof (Artlantis object file) |
| Developer history | Abvent (original developer) → Studio Base 2 (Artlantis RT², current product) |
| Openability | Cannot be meaningfully opened outside Artlantis; no independent viewer or converter exists |
| Released | circa 2000s (with Artlantis Render; exact version undocumented) |
| Latest version | Last classic Artlantis version: Artlantis 2021; successor Artlantis RT² (July 2023) - unclear if it still uses .prw |
PRW conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about PRW files.
