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utf:vmesh

VMeshLibrary

VMeshLibrary stores one or more uniquely named VMeshData entries.

VMeshData

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.

Offset Type Name Description
0x00 uint32 Mesh type Always 1, game crashes otherwise.
0x04 uint32 Primitive type Direct3D primitive type. Default is 4 which is triangle list.
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.

Primitive type can be one of the following:

  1. Points
  2. Line List
  3. Line Strip
  4. Triangle List
  5. Triangle Strip
  6. Triangle Fan

Followed by VMeshGroups.

VMeshGroup

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.

Offset Type Name Description
0x00 uint32 Material ID FL32CRC of material name.
0x04 uint16 Start index Vertex buffer index range defined by start and end.
0x06 uint16 End index
0x0A uint16 Indices count How many indices are used in triangle buffer for this group.
0x0C uint16 Padding Always 0xCC

Followed by triangle buffer and then by vertex buffer.

Parts

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.

VMeshPart/VMeshRef

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.

Offset Type Name Description
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.
0x18 float Min X
0x1C float Max Y
0x20 float Min Y
0x24 float Max Z
0x28 float Min Z
0x2C float Center X Bounding sphere center offset.
0x30 float Center Y
0x34 float Center Z
0x38 float Radius Bounding sphere radius.

Multilevel

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.

VMeshWire/VWireData

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.

utf/vmesh.txt · Last modified: 2019/11/15 10:45 by treewyrm