Expand description


nobject-rs is a library for parsing wavefront .obj and .mtl content. To this end, the crate exposes two methos:

  • load_obj
  • load_mtl

Both methods take the content of the respective files (.obj and .mtl), parse and then return a result with either some kind of parse error, or a struct containing the data.

Note that this crate leaves the responsibility of file I/O to the consuming application. For example, it’s possible to specify file names as attributes in the material, or file names as material libraries in the obj file. This library will NOT attempt to open and parse those files. It is left to the consuming application/library to take the file information from the results of the parse methods, find and open the appropriate files, and then pass on the contents to be parsed.


Parsing is done based on the specification for Obj’s and Mtl’s found at:


Obj parsing

fn main() {
    let input =
    o 1
    v -0.5 -0.5 0.5
    v -0.5 -0.5 -0.5
    v -0.5 0.5 -0.5
    v -0.5 0.5 0.5
    v 0.5 -0.5 0.5
    v 0.5 -0.5 -0.5
    v 0.5 0.5 -0.5
    v 0.5 0.5 0.5
    usemtl Default
    f 4 3 2 1
    f 2 6 5 1
    f 3 7 6 2
    f 8 7 3 4
    f 5 8 4 1
    f 6 7 8 5

    let res = nobject_rs::load_obj(&input).unwrap();
    let group = &res.groups["default"];
    let face_group = &res.faces["default"];
    assert_eq!(res.vertices.len(), 8);
    assert_eq!(group.material_name, "Default".to_string());
    assert_eq!(res.normals.len(), 0);
    assert_eq!(res.faces.len(), 1);
    assert_eq!(face_group.len(), 6);;

Mtl parsing

fn main() {
    let input =
    "newmtl frost_wind
    Ka 0.2 0.2 0.2
    Kd 0.6 0.6 0.6
    Ks 0.1 0.1 0.1
    d 1
    Ns 200
    illum 2
    map_d -mm 0.200 0.800 window.mps";

    let res = nobject_rs::load_mtl(&input).unwrap();
    assert_eq!(res.len(), 1);


Contains information specific to bump maps.

Common settings for texture maps which can be color corrected.

The primary purpose is to store the collection of elements (vertices/normals/texture coordinates) that compose a face. This also contains a smoothing group identifier, as specified by the obj file.

Holds the vertex/texture/normal indicies for a part of a face.

Defines the settings that get applied to a group of faces.

Contains the set of elements which compose a line.

Contains the indicies for a line element.

Defines a single material.

This holds the end result of parsing an obj file. The default group for all models is “default”. That is to say, if no group is defined in a file, a “default” group will be used.

Common settings for texture maps which can not be color corrected.

Representation of normal data.

Contains a set of id’s for the verticies which compose the point collection.

Reflection specific information.

Representation of texture data. v/w are optional.

Representation of vertex data. The w component is optional.


An enum for possible ways of specifying a material color

Enum for the possible ways to specify the disolve

A wrapper for an underlying error which occurred while parsing the token stream.

A wrapper for an underlying error which occurred while parsing the token stream.

The set of errors which might be generated.


Takes the content of an mtl file and parses it.

Takes the content of an obj file and parses it.