Chapter 8 - Render to Texture (3ds Max 2010 Architectural Visualization)
One of the main techniques used to reduce rendering calculation time is to remove all light calculations from a scene. In real time 3D, it is done by pre-processing all lighting solutions prior to loading the 3D content. All these light calculations, complex or not, are put directly into the texture maps of the models. This process is called render to texture or texture baking. More
If you have ever worked in 3ds Max with only rendering in mind, you have probably spent many hours waiting for your renderings to happen. You have tried many tricks to save on rendering time but rarely have you been able to go under a few minutes per rendering, especially when all direct and indirect illumination settings are turned on. You have obtained amazing results at the cost of render time. That is the reality of producing pretty pictures.
Then one day you got some free time (while rendering maybe!), and you sat down in front of your favorite game console to have some fun. At this moment, you noticed how many frames per second were rendered on screen as you played. To give you full interactivity with the game, a game engine needs to produce more than 30 renderings per second. All these rendered frames per second have beautiful lighting and amazing ambiance with soft shading and complex light casting. Interactivity and pretty pictures are the key to give the gamers a great experience as they are moving inside the world of a game.
Game developers have been using tricks to produce high quality images while reducing the amount of rendering time to a fraction of a second per frame. That is true for any industry that needed to develop real time rendering content such as military simulations or virtual reality.
One of the main techniques used to reduce rendering calculation time is to remove all light calculations from a scene. In real time 3D, it is done by pre-processing all lighting solutions prior to loading the 3D content in the interactive game engine. All these light calculations, complex or not, are put directly into the texture maps of the models. This way the main texture of a model includes not only the color of a surface but also the shading of all lights in the scene on that surface. This process is called render to texture or texture baking.
The main idea behind rendering to texture is to take existing materials on a model, calculate all lighting in a scene, and bake it on top of the original material. This way the new material contains light shading and other effects in the scene. Since you can bake a great deal of information from a scene inside a material, you will also see that the same technique can be used to take high polygon count models and bake their surface details in simpler geometry. Reducing polygon count is also an effective way to reduce render time.
In this chapter, you will see that rendering to textures has many applications. Yes, it is fundamental to any game, but you will learn how you can take advantage of this technique to reduce the rendering time of your animated walkthroughs and also to export fully lit models to real time viewers. As painters do, we will start to shade light on surfaces to give them a mood, a greater visual quality, and a better feel for volume, all while being able to contemplate the results in real time, in 3ds Max, or in any other interactive 3D viewer.