<|im_start|>system
You are a helpful AI assistant.<|im_end|>
<|im_start|>user
What do files ending in ".obj" contain?<|im_end|>
<|im_start|>assistant
An OBJ file (.obj) contains information about the geometry of 3D objects. The files are used for exchanging information, CAD, and 3D printing. OBJ files can support unlimited colors, and one file can define multiple objects.

The objects in an OBJ file are defined by polygon faces (which themselves are defined by vertexes, or points) and normals, curves, texture maps, and surfaces. OBJ is a vector file, which makes the defined objects scalable. There’s no maximum file size.

The format was created in the 1980s by Wavefront Technologies for its Advanced Visualizer animation software (Autodesk Maya has since replaced Advanced Visualizer). The file extension OBJ comes from the name Wavefront OBJect (the full name is rarely used). Other companies have adopted the OBJ format for use in their applications.<|im_end|>
<|im_start|>user
tell me more about what programs can use the .obj file format.<|im_end|>
<|im_start|>assistant
The .obj file format is typically used with 3D viewing and modeling programs such as Blender. It can also be used with a 3D printer to create a real life rendition of the three dimensional object it represents. If a dedicated 3D viewer is not available Adobe Photoshop can also open a .obj file.<|im_end|>
<|im_start|>user
This ".obj" file is part of a 3D model.<|im_end|>
<|im_start|>assistant
In that case, the .obj file contains the mesh geometry of the 3D model in plain text Wavefront OBJ format. This includes the position, texture coordinates, and normals for vertices, and how those vertices are connected to form faces and lines.
Material and texture information for the 3D model is not included in the .obj file and is in an external .MTL file instead.<|im_end|>