![]() ![]() No spaces are permitted before or after the slash.Ī valid texture coordinate index starts from 1 and matches the correspondingĮlement in the previously defined list of texture coordinates.Įach face can contain three or more elements. One must put a slash immediately after the vertex index and then put the To add a texture coordinate index to a vertex index when defining a face, Optionally, texture coordinate indices can be used to specify texture coordinates when defining a face. If an index is negative then it relatively refers to the end of the vertex list, -1 referring to the last element.Įach face can contain three or more vertices. ![]() If an index is positive then it refers to the offset in that vertex list, starting at 1. OBJ files also support free-form geometry which use curves and surfaces to define objects, such as NURBS surfaces.Ī valid vertex index matches the corresponding vertex elements of a previously defined vertex list. Polygons such as quadrilaterals can be defined by using more than three indices. u only is required for curve points, u and v for surface points and control points of non-rational trimming curves, and u, v and w (weight) for control points of rational trimming curves.įaces are defined using lists of vertex, texture and normal indices in the format vertex_index/texture_index/normal_index for which each index starts at 1 and increases corresponding to the order in which the referenced element was defined. Define points in parameter space of a curve or surface. Parameter space vertices Ī free-form geometry statement can be specified in a line starting with the string vp. ![]() Some applications support vertex colors, by putting red, green and blue values after x y and z (this precludes specifying w). A right-hand coordinate system is used to specify the coordinate locations. # Parameter space vertices in (u, ) form free form geometry statement (see below)Ī vertex is specified via a line starting with the letter v. # List of vertex normals in (x,y,z) form normals might not be unit vectors. # List of texture coordinates, in (u, ) coordinates, these will vary between 0 and 1. # List of geometric vertices, with (x, y, z, ) coordinates, w is optional and defaults to 1.0. The most common elements are geometric vertices, texture coordinates, vertex normals and polygonal faces: OBJ coordinates have no units, but OBJ files can contain scale information in a human readable comment line.Īnything following a hash character (#) is a comment.Īn OBJ file may contain vertex data, free-form curve/surface attributes, elements, free-form curve/surface body statements, connectivity between free-form surfaces, grouping and display/render attribute information. Vertices are stored in a counter-clockwise order by default, making explicit declaration of face normals unnecessary. The OBJ file format is a simple data-format that represents 3D geometry alone - namely, the position of each vertex, the UV position of each texture coordinate vertex, vertex normals, and the faces that make each polygon defined as a list of vertices, and texture vertices. The file format is open and has been adopted by other 3D graphics application vendors. OBJ) is a geometry definition file format first developed by Wavefront Technologies for its Advanced Visualizer animation package. ![]()
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