VMeshLibrary stores one or more uniquely named VMeshData entries.
VMeshData is pretty much a big vertex/index buffer that contains all vertices and triangles of one or multiple parts. However when containing meshes of multiple parts VMeshData isn't directly aware of how many has, it's a dumb storage, but an indirect indication that another part begins within its data set is when VMeshGroup.vertexStart is 0 and when vertex index in triangle also starts from 0. Normally parts never share vertices, but mesh groups within a part may.
VMeshRef points to range of indices, vertices and mesh groups.
|0x00||uint32||Mesh type||Always 1, which may indicate it is a rigid body mesh.|
|0x04||uint32||Surface type||Always 4. May refer to hitbox format mesh uses.|
|0x08||uint16||Group count||How many individual mesh groups contained there.|
|0x0A||uint16||Indices count||How many indices are used for triangle buffer.|
|0x0C||uint16||FVF||Direct3D Flexible Vertex Format.|
|0x0E||uint16||Vertex count||How many vertices stored here.|
Followed by VMeshGroups.
A group is a collection of vertices and vertex indices forming triangles that are grouped by a single material identifier. It is fairly common in Freelancer for a model or even an individual part of a compound model to use multiple materials. So a model or each of its parts may use one more groups if they use multiple materials.
|0x00||uint32||Material ID||FL32CRC of material name.|
|0x04||uint16||Start index||Vertex buffer index range defined by start and end.|
|0x0A||uint16||Indices count||How many indices are used in triangle buffer for this group.|
Followed by triangle buffer and then by vertex buffer.
Individual parts of compound mesh are usually stored as whatever.3db entry in UTF root, sometimes name contains timestamp, sometimes has lod0 added to as well, but ultimately the name of entry is irrelevant so long as it's not one of the other common ones that would confuse loading procedure. This entry name is referred within File name node in parts listing within Cmpnd.
Contained within VMeshPart it has no mesh data of its own and instead refers to specific VMeshData by CRC of entry name and points to ranges of vertices, indices and mesh groups that would form up the mesh of the individual part.
It is possible for multiple VMeshRefs to point to exact same ranges of the same VMeshData, which allows to save up some space and introduces re-usable instanced geometry where multiple parts of the model may use exactly same geometry but via joint transformation located in different positions.
VMeshRef may also use 0 vertices, indices and mesh groups making such part by itself an invisible dummy. This can be used to create proxy parts to provide additional axis or types for constrained joint animation.
|0x00||uint32||Size||VMeshRef size. It's always 60 bytes.|
|0x04||uint32||VMeshData reference||Points to VMeshData entry (internally or externally) by its hashed name|
|0x08||uint16||Vertex start||Start vertex index in vertex buffer.|
|0x0A||uint16||Vertex count||How many vertices in vertex buffer are used.|
|0x0C||uint16||Index start||Start triangle vertex index in triangle buffer.|
|0x0E||uint16||Index count||How many vertex indices in triangle buffer are used.|
|0x10||uint16||Group start||Start mesh group.|
|0x12||uint16||Group count||How many mesh groups are used.|
|0x14||float||Max X||Bounding box corner vertices.|
|0x2C||float||Center X||Bounding sphere center offset.|
|0x38||float||Radius||Bounding sphere radius.|
Each part may have several LOD meshes independent of other parts in modVMeshPart /el. VMeshRef then are used within Level entries indicating LOD and Switch2 entry specifying ranges of each level. Switch2 is often overridden within INI files with LODRanges property instead but will be used in its absence.
Contains a list of vertex index pairs forming sequence of lines drawn between the pairs. Wire mesh typically is used in HUD for inspecting and selecting subparts of the currently targeted object. Other than using vertex indices lines are completely arbitrary and don't have to follow original mesh geometry or its actual edges. Wire mesh is purely for schematic visualization.
VWireData can refer to any VMeshData and not necessarily the same one, often times it refers to farthest LOD for fewer lines to draw. You could even use vertices in VMeshData that aren't even used in any VMeshRefs to draw something completely different.