Reference mesh

In Source, a Reference mesh (sometimes called the body or envelope or skin of the model) defines some or all of a model's rendered geometry. A model needs at least one reference mesh or it will not be visible in the world. It is enveloped to the bones of a model's Skeleton and moves with them. It is commonly replaced by lower-detail meshes at distances with $lod.

A reference mesh includes:

Geometry data

Vertex Coordinates (relative to a specific Parentbone) for each triangular polygon,

Smoothing group data

Normal vector (relative to a specific Parentbone) at each vertex,

Skinning

UV map coordinates and Default Skinname(s),

Envelope data

Weight map values and Parentbone for each vertex.

Tip:See SMD file format for exactly how this data is stored in the triangles block of a "Studio Model Data" file.

Default mesh

The Default mesh is the Mesh that will be rendered unless substituted by a specific LOD mesh, and/or modified by a specific Sub-mesh.

• It is defined in the Reference.smd and compiled to the VVD and VTX binaries via the $body or $model QC command.

Sub-mesh

Sub-meshes can be switched on and off at runtime. Like the Default mesh, they are enveloped to the model's Skeleton, and will deform (stretch and bend) as if part of the Default mesh. Specific pieces of clothing are good candidates for switchable sub-meshes; eg different types of body armor or headgear. By contrast Sub-models (eg weapons) can be attached to specific $attachment points on this skeleton, but they remain enveloped to their own skeleton; they will move with this skeleton but will not be deform by it.

• The $bodygroup configuration allows any number of sub-meshes (SMDs) to be added to the Default mesh. Setting up multiple $bodygroups allows sub-mesh switching to be triggered by (code-level) events.
• Sub-meshes do not affect the model's collision model.
• (
  Todo: $model's face mesh for facial animation ?
  )

LOD mesh

Source's LOD system allows a "cheaper" (simplified) version of the Mesh(es) to be rendered at a distance where the loss of "expensive" detail is not noticeable to the Viewer. Any number of replacement LOD_Mesh.SMDs are usually created from pared-down versions of the Default Mesh and Sub-Meshes, but they are compiled into the main MDL's VVD and VTX files via the QC $lod configuration. The Default Mesh (including Sub-Meshes) is used when no LOD Mesh is active, we could say it amounts to an "lod0" Mesh.

See also

• $body / $model
• $bodygroup
• $lod