Studiomdl Data
- SMD has been superseded by the DMX model format.
The Studiomdl Data file format (SMD) stores 3D models in ASCII for analysis and compilation by studiomdl. SMD files are usually generated by an SMD export plug-in for a given model editor package like MilkShape.
Aside from Source and GoldSrc, SMD is known to be used by Sauerbraten and third party tools for The Sims and Mount & Blade.
General notes
- X is north in SMD. Elsewhere in Source it is east.
- The format is carriage return sensitive: Linux-based text editors should use CR or CRLF line terminators instead of just LF. each command must be on a separate line. There should also be a single blank line at the end (and only the end) of the file.
- White space is the only delimiter: any combination of tabs and spaces can be used to separate values, and for this reason multiword names should be enclosed in "quotation marks".
Bug: Avoid using tab. Its presence can crash studiomdl in very large SMDs.
- Stand-alone line comments start with // (double foreslash)
- End-line comments start with # (hashtag) or ; (semicolon)
Types
- Reference / Collision
- A complete snapshot of the model, including one frame of animation to define the default pose. Collision meshes follow the same pattern.
header
nodes
skeleton
triangles
- Animation
- A single skeletal animation.
header
nodes
skeleton
- Vertex
- A flex animation library. Usually has extension
.vta
. header
nodes
skeleton
(a "time <n>" header for each flex shape; no position data required)vertexanimation
Data blocks
Here are the components of an SMD file, considered in order:

Header
Simply:
version 1
Nodes
A list of all the bones in the model.

Syntax
-
nodes
- Starts the node block.
-
<int|ID> "<string|Bone Name>" <int|Parent ID>
- A bone definition. Unique ID number (does not have to be sequential), name in quote marks and the parent bone's ID. Bones without parents (i.e. children of the world) have a Parent ID of
-1
.Note:Studiomdl matches bones across SMDs by name. IDs are internal to each file.
-
end
- Ends the data block.
Example
A root bone with one child:
nodes 0 "root" -1 1 "child" 0 end
Skeleton
Position data for each bone in each animation frame. In a reference SMD there is only one frame, which contains the model's default posture.

Syntax
-
skeleton
- Begins the skeleton block.
-
time <int>
- Begins a new frame. Any range of numbers can be used, so long as they increase sequentially.
-
<int|bone ID> <float|PosX PosY PosZ> <float|RotX RotY RotZ>
- A bone's position relative to its parent (give absolute values in the case of root bones).
-
Pos
is position in units. -
Rot
is local Euler angles, given in radians. (90° = 1.570796 rad)
-
Tip:The first frame must include all bones. After that, those which have not moved relative to their parent since the last frame can be omitted.
Tip:Converting from a local rotation matrix to Euler angles might require you to invert the rotation matrix before conversion.
-
end
- Ends the data block.
Example
Bone 1 move two units along the Y axis, then back again:
skeleton time 0 0 0 0 0 1.570796 0 0 1 1 0 0 0 0 0 time 1 1 1 2 0 0 0 0 time 2 1 1 0 0 0 0 0 end
Triangles
A triangle in a model is defined by three vertices. Included in each triangle is its UV co-ordinates and envelope weights.

Syntax
-
triangles
- Begins the triangle block.
-
<material>
- Defines the start of a new triangle and the material to apply to it. Anything after a '.' (e.g. a file extension) is ignored. Do not enclose in quotes and do not include a path ($cdmaterials will provide one).
-
<int|Parent bone> <float|PosX PosY PosZ> <normal|NormX NormY NormZ> <normal|U V> <int|links> <int|Bone ID> <normal|Weight> [...]
- Defines a vertex.
-
Pos
is in world units -
Norm
is used to smooth the surface of the model (See: Normal (geometry)) - U and V are the vertex's UV map co-ordinates
-
- The final three values are optional: they override
<Parent bone>
to define a series of weightmap links.Bone ID
andWeight
are repeated for each link. If the weights do not add up to 1, any remaining value is placed on<Parent bone>
.Note:For SMDs included with $lod, Studiomdl can determine a vertex's weight links by copying those of the closest reference mesh vertex.
-
end
- Ends triangle block.
Example
A flat, two-sided square. The left edge envelopes bone 0 and the right edge envelopes bone 1, and the UV map is a simple square projection:
triangles my_material 0 0 0 0 0 0 1 0 1 1 0 1 0 0 -1 0 0 0 1 0 0 1 0 1 1 1 -1 0 0 0 1 1 0 1 1 1 my_material 0 0 0 0 1 0 1 0 1 1 0 1 1 1 -1 0 1 0 1 1 0 1 1 1 1 1 0 0 1 0 1 1 1 1 1 1 my_material 1 1 -1 0 0 0 1 1 0 1 1 1 0 0 -1 0 0 0 1 0 0 1 0 1 0 0 0 0 0 0 1 0 1 1 0 1 my_material 1 1 0 0 1 0 1 1 1 1 1 1 1 1 -1 0 1 0 1 1 0 1 1 1 0 0 0 0 1 0 1 0 1 1 0 1 end
Vertexanimation
Position of vertices in various morph targets, for use in flex animation. While this block uses the same time
keyword as skeleton
, each 'frame' is instead a discrete, static shape. Transitions between them are created on-demand by the engine.

nodes
and a skeleton
block are needed in each VTA. The skeleton block needs only contain a "time <n>" header for each flex shape.Syntax
-
vertexanimation
- Begins the vertex animation block.
time <int>
- Begins a morph target. The first target must include all vertices on the mesh in their reference positions; subsequent targets should include only vertices that differ from the reference.
-
<int|ID> <float|PosX PosY PosZ> <normal|NormX NormY NormZ>
- A vertex.
-
end
- Ends the data block.