CS426 Video 14 Wavefront Object Files Flashcards

Flashcards based on lecture notes about Wavefront Object files and 3D modeling formats.

OBJ file format

A file format for representing 3D object geometry, commonly used in 3D graphics.

Platonic Solid

A convex polyhedron where all faces are congruent regular polygons, faces only intersect at edges, and an equal number of faces meet at each vertex.

Fibonacci Numbers

1, 2, 3, 5, 8, 13… The ratio of the last two numbers tends towards 1.618.

Golden Ratio (phi)

Approximately 1.618, it is related to Fibonacci numbers.

The 5 Platonic Solids

Tetrahedron, Octahedron, Icosahedron, Cube (Hexahedron), Dodecahedron

Euler’s Formula

𝑉 − 𝐸 + 𝐹 = 2

Euler characteristic 𝜒=2

Sphere

Euler characteristic Torus

χ = 0

Archimedean solid

A convex uniform polyhedron composed of regular polygons meeting in identical vertices, excluding the five Platonic solids.

cube1.mtl

A type of file in Blender.

Materials file

Ambient, Diffuse, Specular

New material

Illumination mode (highlight on)

New untextured material

Ambient green, Diffuse green

What does a typical OBJ file contain?

Vertices, Faces & UV coordinates

Vertices in Object file

Representation of vertices (corners of cube) and their positions.

Example of vertex list

0 0 0
0 0 1
0 1 1
0 1 0
1 0 1
1 1 1
1 1 0

Faces in Object file (Polygons)

Representation of polygons forming the object.

Example of texture coordinate (U,V)

0.667 1.000
0.500 1.000
0.500 0.000
0.667 0.000

Exporting a model to Polygon File Format (.PLY) in blender requires the user to select the following options:

File > Export > .ply

PLY: Polygon File Format

A file format that contains vertex, face, color, normal and texture information of a 3D model.

STL (Stereolithography)

A file format that represents 3D object geometry using triangles.

Beginning line of STL file

Exported from Blender-2.82 (sub 7)

Example of File structure for FBX

Geometry, Vertices, PolygonVertexIndex, Edges, LayerElementNormal, LayerElementUV, LayerElementMaterial, Layer, Model

What other file types and details does FBX contain?

Details of lighting and camera etc..

Beginning of dae formatted object

What other file types and details does dae contain?

Details of lighting and camera etc..

List of 3D file types

Wavefront, PLY, STL, FBX, DAE