There is an operation called "rendering" in video or 3D. What does it do? Why is it called "rendering"?

Rendering is called Render in English, and some people call it shading, but I am more accustomed to calling Shade shading and Render called . Because the words Render and Shade values ??are two completely different concepts in 3D software, although their functions are very similar, they are different. Shade is a display scheme that generally appears in the main window of 3D software. It plays the same role as the wireframe of the 3D model in assisting in observing the model. Obviously, shading mode makes it easier for us to understand the structure of the model than wireframe mode, but it is just a simple display. It is called shading in digital images. In advanced 3D software like Maya, you can also use Shade to display simple lighting effects, shadow effects and surface texture effects. Of course, high-quality shading effects require the support of a professional 3D graphics display card, which can accelerate and Optimize the display of 3D graphics. But no matter how optimized it is, it cannot turn the displayed three-dimensional graphics into high-quality images. At this time, because Shade uses a real-time display technology, and the speed of the hardware is limited, it cannot feedback the reflection and refraction in the scene in real time. and other ray tracing effects. In real work, we often need to output models or scenes into image files, video signals or film films, which must go through the Render program.

The Shade window provides a very intuitive and real-time basic surface shading effect. Depending on the capabilities of the hardware, it can also display texture maps, light source effects and even shadow effects, but all of this is rough, especially Without hardware support, its display may even be irrational and disorderly.

The Render effect is different. It is calculated based on a complete set of programs. The impact of the hardware on it is only a speed issue and will not change the results of . The result depends on what program it is rendered based on, such as ray tracing or radiosity.

The basic process of rendering

First, the camera in the three-dimensional scene must be positioned, which is the same as real photography. Generally speaking, 3D software has provided four default cameras, which are the four main windows in the software, divided into top view, front view, side view and perspective view. Most of the time we render a perspective view rather than other views. The perspective camera basically follows the principle of a real camera, so the results we see will be the same as the real three-dimensional world, with a three-dimensional feel. . Next, in order to reflect the sense of space, the rendering program has to do some "special" work, which is to determine which objects are in front, which objects are behind, and which objects are occluded. The sense of space cannot be perfectly reproduced only through the occlusion relationship of objects. Many people who are new to 3D only pay attention to the shaping of the three-dimensional sense and ignore the sense of space. You must know that the sense of space is closely related to the attenuation of the light source, environmental fog, and depth of field effects.