3D Rendering Fundamentals

At the most basic level, rendering of 3D content is accomplished by using matrix and vector mathematics to transform points and directions between various coordinate spaces.

Understanding a few of the underlying concepts will help a designer make informed decisions when configuring 3D Model render extensions in Storyboard Designer. Below we will explain the coordinate spaces that are applicable to 3D rendering in Storyboard and explain how they relate to the properties of the 3D Model render extension.

World space is a three dimensional space that serves as the basis for defining all the other coordinate spaces. The locations of the camera and model in the 3D Model render extension properties are coordinates in world space. It is important to note that each 3D Model render extension instance references its own model data and is effectively a 2D portal into a distinct three dimensional world.

In Storyboard, we define the default position and orientation of the camera to be at the origin of World space and looking down the World space negative z-axis. There are 2 primary camera modes which determine the effect of the Camera parameters on defining View space (also called Camera space).

In “Orbit” mode, the Azimuth and Elevation parameters first rotate View space around the World space y-axis and x-axis (respectively). The camera X, Y, Z position then position the camera in this rotated space. By defining View space using transformations in this order, we can achieve a neat effect. If we set only the Z position of the camera, Azimuth and Elevation now spin the camera around the World space origin, with the camera always looking toward the origin.

In “Fly” mode, the camera X, Y, Z position define the position of the origin (0,0,0) of View space within world space. Azimuth and Elevation now rotate the View space around the y-axis and x-axis (respectively) of View space. This allows a camera that can freely look “away” from the World space origin in any direction.

You may notice in the above description that the above descriptions of Azimuth and Elevation are in terms of y-axis and x-axis, and not the z-axis. In order to simplify rotations, Storyboard does not allow the camera to be “rolled” along the View z-axis.

The 3D Model render extension takes as a parameter a single model file per instance. Storyboard supports .obj and .fbx files as 3D model input. Since FBX file support is provided by a closed-source library maintained by Autodesk. This library has support for limited number of platforms and architectures. To help mitigate this limitation, and provide an opportunity for offline optimization of model data, FBX files are converted on import to SSG (Storyboard Scene Graph) files.