View source for VRM

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'''VRM''' is a model file format supported by {{src}} [[StudioMDL (Source 1)|StudioMDL]]. It was developed as a successor to [[SMD]], but ultimately was scrapped in favor of sticking with SMD, and later [[DMX]]. The main distinction between the formats is that VRM supports multiple [[LoD]]s in a single file, using [[w:Intel|Intel]]'s proprietary Multi-Resolution Mesh (MRM) technology.

{{confusion|The VRM file extension is also used for an [https://vrm-consortium.org/en/ unrelated VR model format].}}

== Data blocks ==

Here are the components of a VRM file, considered in order:

{{note|This document has been written assuming you already know how an [[SMD]] file works.}}
{{warning|This document does NOT (at the moment) detail ANY info on how VRM implements MRM.}}

=== Header ===

 version 2
 name "<[[string]]|Object Name>"
 vertices <[[int]]|Amount of vertices>
 faces <[[int]]|Amount of faces>
 materials <[[int]]|Amount of materials>
 texcoords <[[int]]|Amount of texture coordinates>
 normals <[[int]]|Amount of normals>
 tristrips <[[int]]|Amount of tristrips>

==== Name ====

Defines the name for the object, this is ignored by [[StudioMDL (Source 1)|StudioMDL]].

==== Vertices ====

Defines the amount of vertices used in the mesh.

==== Faces ====

Defines the amount of faces (triangles) used in the mesh.

==== Materials ====

Defines the amount of materials (textures) used in the mesh.

==== Texcoords ====

Defines the amount of texture coordinates (UVs) used in the mesh.

: {{warning|This value has to be above 0, as otherwise [[StudioMDL (Source 1)|StudioMDL]] will crash with an error.}}

==== Normals ====

Defines the amount of normals used in the mesh.

==== Tristrips ====

Always 0.
 {{note|StudioMDL ignores this, so you *could* use any value you want.}}

=== Nodes ===

Works exactly the same as in [[SMD#Nodes|SMD]].

=== Skeleton ===

Works exactly the same as in [[SMD#Skeleton|SMD]].

=== Vertexlist ===

List of vertices.

==== Syntax ====

; <code>vertexlist</code>
: Begins the block.
; <code><[[int]]|Vertex ID> <[[int]]|Parent bone> <[[float]]|PosX PosY PosZ> <[[int]]|Links> <[[int]]|Bone ID> <[[float]]|Weight> [...]</code>
: Defines a [[vertex]].
:* <code>Pos</code> is in world [[unit]]s
: The final three values are optional: they override <code><Parent bone></code> to define a series of [[weightmap]] links. <code>Bone ID</code> and <code>Weight</code> are repeated for each link. If the weights do not add up to 1, any remaining value is placed on <code><Parent bone></code>.
; <code>end</code>
: Ends the block.

=== Facelist ===

List of faces (triangles).

==== Syntax ====

; <code>facelist</code>
: Begins the block.
; <code><[[int]]|Face ID> <[[int]]|VertID1 VertID2 VertID3></code>
: Defines a triangle.
; <code>end</code>
: Ends the block.

=== Materiallist ===

List of materials.

==== Syntax ====

; <code>materiallist</code>
: Begins the block.
; <code><[[int]]|Material ID> <[[float]]|ARed AGreen ABlue AAlpha> <[[float]]|DRed DGreen DBlue DAlpha> <[[float]]|SRed SGreen SBlue SAlpha> "<[[string]]|Texture Path>"</code>
: Defines a material.
; <code>end</code>
: Ends the block.

=== Texcoordlist ===

List of texture coordinates (UVs).

==== Syntax ====

; <code>facelist</code>
: Begins the block.
; <code><[[int]]|Texture coordinate ID> <[[float]]|U V></code>
: Defines a texture coordinate.
; <code>end</code>
: Ends the block.

=== Normallist ===

List of normals (normal vectors).

==== Syntax ====

; <code>normallist</code>
: Begins the block.
; <code><[[int]]|ID> <[[int]]|Bone ID> <[[float]]|NormX NormY NormZ></code>
: Defines a normal.
; <code>end</code>
: Ends the block.

=== Faceattriblist ===

List of faces, again, but now with extra attributes.

==== Syntax ====

; <code>facelist</code>
: Begins the block.
; <code><[[int]]|Face ID> <[[int]]|Material ID> <[[int]]|Smooth> <[[int]]|TexCoordID1 TexCoordID2 TexCoordID3> <[[int]]|NormID1 NormID2 NormID3></code>
: Defines attributes for a face.
; <code>end</code>
: Ends the block.

== External links ==
* [https://github.com/Source-SDK-Archives/source-sdk-2004/blob/master/src_mod/utils/studiomdl/mrmsupport.cpp#L680 VRM parser in the Source 2004 SDK]
* [https://valvearchive.com/articles/vrm/ Article about VRM and 3DS Max plugin on Valve Archive]
* [https://web.archive.org/web/19990910123935/http://sierrastudios.com/games/teamfortress/ TF2 Brotherhood of Arms official website (archived)], which discusses MRM technology
* [https://github.com/UnBeatWaterGH/valve-vrm/blob/main/vrmtosmd.py Python script allowing for VRM to SMD conversion]

[[Category:Plain text formats]]
[[Category:File formats]]