Why are games rendered with a GPU while Blender, Cinebench and other programs use the CPU to render high quality 3d imagery? Why do some start rendering in the center and go outwards (e.g. Cinebench, Blender) and others first make a crappy image and then refine it (vRay Benchmark)?
In: Technology
Almost every 3D software has its own rendering engine that’s different from others by the kinds of calculations it does in order to produce an image.
– Videogame engines are optimized to do rendering in real-time, and GPUs are in turn optimized to help them achieve that. Making the quality as good as possible while being able to render 30/60/240 frames per second. Videogames do *a lot* of shortcuts and clever tricks do make the image look great with minimal computing. Like normal maps, baking in lighting, a plethora of shaders, lots of post-processing, etc.
– Professional 3D rendering engines are optimized for quality and realism. As in, putting an actual light in the scene, and calculating how the rays will bounce off the objects and into the camera. Those kinds of calculations take more time, but produce much better results and are more flexible.
But when it’s all said and done, the rendering calculations themselves can be processed by the CPU or GPU cores, depending on which will do the task faster/cheaper/more energy efficient with the software in question.
You can try it for yourself with Blender. Take any scene, and render it out using Cycles renderer. First using a GPU and then a CPU to see how they’ll perform. A GPU will render one sector at a time, but very fast, whereas a CPU will render multiple sectors at once (with each of its physical cores), but each sector will take longer to render.
But that’s an ELI5 version, 3D rendering is one of the most mathematically complex subjects in computer science and I’m too uneducated to dive into more details.
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