In this tutorial we will render a walk-through animation of a static scene, where nothing but the camera moves. We will use global illumination to light the scene, which makes the task somewhat complicated. GI is usually too slow to calculate from scratch and with sufficient quality for each frame of the animation. To optimize this process and save rendering time, we can use the fact that the scene is static and the camera is the only thing that moves. Most of the GI solutions used in V-Ray (irradiance map, photon map, light cache) are either fully or partially view-independent, and we can use this fact to reduce rendering times.
For this tutorial, we will use the irradiance map as a primary GI engine, and the light cache as a secondary engine. To make the process easier to understand, we will render the scene in three steps.
In the first step, we will calculate the light cache for the entire animation. In the second step, we will calculate the irradiance map. In the third step, we will render the final animation.
Note that you don't have to use this method to render walk-throughs. You can always use a slower brute-force approach and avoid having to deal with all the issues around precalculating the various GI solutions. However, you pay for this with render times.