What is Open Asset Import Library?

Open Asset Import Library, in short Assimp, is a cross-platform library to import and convert 3D model files. The different file formats are converted into a hierarchical data structure, enabling a programmer to support a wider range of model formats in a single, comprehensive way.

Figure 1.20 shows the key elements and their relationships:

Figure 1.20: A simplified version of Assimp’s data structures

Let us take a closer look at these data structures and their functions:

• aiScene is the central element of Assimp’s data structure. The root node entry, all information about the polygonal meshes, the materials, and the animations are stored in the aiScene element.
• The root node of aiScene points to a structure called aiNode. In every aiNode, possible child nodes are stored, eventually creating a node tree. Also, a transform matrix resides in the aiNode structure, defining the local transformation, relative...