Wavefront Object

Use

You can import and view Wavefront Object (.obj) files.

The .obj file format was developed for the Wavefront application developed by Alias. The format stores a description of the surface of a 3D object, composed of triangles or higher degree polygons.

Supported for Import

The .objf file format, (a derivative of the .obj format), is supported. Stripe files have the following file structure:

  • Vertex data: Geometric vertices (v), texture vertices (vt), and vertex normals (vn)

  • Elements data: Triangle strip (t) and triangle strip continuation (q)

Supported for Export

  • Associated materials exported as .mtl files

  • Groups read as separate objects

  • Polygonal objects and free-form objects. Polygonal geometry uses points, lines, and faces to define objects while free-form geometry uses curves and surfaces. SAP 3D Visual Enterprise Author reads only polygonal geometry

  • Texture coordinates

Features

This format contains both import and export options. You can use them to customize the way in which your file is opened and saved.

Import Interface

Field

Functional Description

Import Material File

Imports all material information from the .mtl file

Flip Coordinate System

Rotates the model so it uses a right-hand coordinate system. That is, it flips the Y and Z axes.

Export Interface

Field

Functional Description

Common

Defines the general settings

  • Compact Data: Optimizes all vertices, normals, and texture coordinates by and compresses the data by removing any duplicate items

  • Create Material File: Saves all material information in the .mtl file

  • Export Vertex Normals: Saves the vertex normals in the .obj file

  • Export Texture Coordinates: Saves any (u,v) texture coordinates that are assigned to face vertices in the .obj file

  • Triangulate Non-Flat Polygons: Converts all non-flat polygons to triangles

  • Flip Coordinate System: Rotates the model so it uses a left-hand coordinate system. That is, it flips the Y and Z axes.

  • Create SubD Control Mesh: Creates low detail, low polygon count subdivision control mesh with models that contain SubDs. This mesh is subdivisible.

  • Max Vertices in Polygon: Exports polygons containing fewer than or equal to the specified number of vertices. This reduces the file size.

  • Replace Material Colors: Replaces material colors (ambient, diffuse, and specular) with white if the same texture is present and if the texture blending mode is set to “Replace”. This ensures the saved file more closely resembles the source scene.

  • Maximum String Length Before Wrap: Sets a specific string length before wrapping

Number of Digits after the Decimal Point

Manages double precision output

  • Vertices (v): Optimizes precision for geometric vertices

  • Normals (vn): Optimizes precision for vertex normals

  • UVs (vt): Optimizes precision for texture vertices

Example

The following is an example of a Stripe file:

v 0.000000 0.000000 1.000000 # Vertex 1v 1.000000 1.000000 0.000000 # Vertex 2v 2.000000 0.000000 0.000000 # Vertex 3v 3.000000 1.000000 0.000000 # Vertex 4v 4.000000 0.000000 0.000000 # Vertex 5v 3.000000 -1.000000 0.000000 # Vertex 6v 4.000000 -1.000000 0.000000 # Vertex 7v 2.000000 2.000000 0.000000 # Vertex 8v 3.000000 2.000000 0.000000 # Vertex 9v 3.000000 3.000000 0.000000 # Vertex 10t 10 9 8 # Start of triangle strip 1q 4 # Continuation of triangle strip 1q 2 # Continuation of triangle strip 1q 3 1 # Continuation of triangle strip 1t 3 4 3 5 # Start of triangle strip 2q 6 7 # Continuation of triangle strip 2

The following is an example of an .obj file:

v 0.000000 2.000000 2.000000v 0.000000 0.000000 2.000000v 2.000000 0.000000 2.000000v 2.000000 2.000000 2.000000v 0.000000 2.000000 0.000000v 0.000000 2.000000 0.000000v 2.000000 0.000000 0.000000v 2.000000 2.000000 0.000000f 1 2 3 4f 8 7 6 5f 4 3 7 8f 5 1 4 8f 5 6 2 1f 2 6 7 3