.LWO File Format

Introduction

LWO is the object format of LightWave 3D, the modelling and animation package that began on the Amiga with NewTek’s Video Toaster. An object file holds the geometry and its surfaces; the scene, with lights, cameras and animation, is saved separately as a .lws file.

There are two generations. Older files, from LightWave 5 and earlier, have the form type LWOB. LightWave 6 introduced LWO2, which adds layers, vertex maps for texture coordinates and weights, and a new surface system. NewTek documented both in its developer kit.

Structure

An LWO file is an IFF file, the chunk format from Electronic Arts used widely on the Amiga. It is one big-endian FORM chunk with the form type LWO2 or LWOB, holding further chunks, each a four-letter ID, a length and the data. In an LWO2 file the main chunks are TAGS (the names of surfaces and parts), LAYR (the start of a layer), PNTS (point positions), BBOX, VMAP (per-point values such as texture coordinates), POLS (polygons as lists of point numbers), PTAG (which surface each polygon uses), CLIP (images) and SURF (surface settings).

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