What is the LWO file format?
.lwo files contain three-dimensional objects and the information describing them, used natively in LightWave 3D - software for creating and animating 3D structures. Stored within .lwo files are points, polygons, and surfaces that define three-dimensional models, along with references to image clips used for the model's textures and materials.
The format is built on IFF (Interchange File Format) FORM chunks, identified by the four-byte signature FORM at the start of the file, followed by LWO2 at offset 8. Two main variants exist: the original LWOB (LightWave 1-5.x, circa 1994) and LWO2, introduced in LightWave 6.0 (2001), which added multi-layer support and richer material definitions. A further variant, LWO3, appeared in LightWave 2015+.
.lwo files are saved in a proprietary but publicly documented format, allowing them to be used across multiple versions of LightWave 3D. They are employed to transfer three-dimensional objects - created from scratch or modified - between different machines or versions of the application. Three-dimensional models stored in .lwo files can also be imported into other popular applications such as Blender and Modo.
LightWave 3D was acquired by LightWave Digital in April 2023, which restarted active development and released LightWave 2025. For broader cross-application pipelines, FBX and glTF are now more widely used interchange formats.
Security & safety
RISK: LOWLWO is a passive 3D data file - it does not execute code. Texture paths may reference external files; loading in a 3D app will look for those paths. No known malware vectors specific to LWO.
Format details
in a nutshell- Modo Object file (.lwo) - Foundry's Modo 3D modeler also uses .lwo natively, as it shares roots with LightWave's modeler lineage.
Programs that open LWO files
Windows4 apps
Blender
Open-source Built-in LWO importer: File > Import > LightWave Object (.lwo). Supports LWO2; LWOB support may be partial. 
3D Object Converter
Paid Batch conversion utility; import LWO and export to OBJ, FBX, X, STL and 50+ other formats. 
macOS3 apps
Linux1 app
Technical details
deep spec| Container | IFF FORM chunk - same root standard as AIFF audio and ILBM images |
| Magic bytes | `FORM` at offset 0; form type `LWO2` at offset 8 (or `LWOB` for legacy files, `LWO3` for LightWave 2015+) |
| Byte order | Big-endian (IFF convention) |
| Format variants | `LWOB` (LightWave 1-5.x, 1994); `LWO2` (LightWave 6+, 2001); `LWO3` (LightWave 2015+) |
| Key sub-chunks | `LAYR` (layer), `PNTS` (points), `POLS` (polygons), `SURF` (surface/material), `TAGS`, `PTAG`, `CLIP` (texture clips), `BBOX` (bounding box) |
| Multi-layer support | `LWO2` and later support multiple named layers within a single file |
| Surface/material model | Per-polygon surface tags referencing full material definitions including shader parameters, texture maps, and environment settings |
| Chunk size encoding | `LWOB` uses 2-byte sub-chunk sizes; `LWO2` uses variable-length index (VX) encoding for most fields |
| Dimensions | No documented polygon count or coordinate range limit; practical limit is application RAM |
| SDK | Format specification and SDK publicly documented by LightWave Digital |
| Developer history | NewTek → Vizrt (2019) → LightWave Digital (April 2023); LightWave 2025 released under new ownership |
| MIME type | `application/x-lightwave-object` |
| Released | 1994 (original LWOB format in LightWave 3D for Amiga/early Windows) |
| Latest version | LWO2 (introduced in LightWave 6.0, ~2001); LWO3 variant in LightWave 2015+ |
| Specification | docs.lightwave3d.com |
LWO conversions
Community Q&A
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