今天只是更新了各个概念的定义和区分，后续会继续update本文，譬如：会添加各个技术在不同领域的应用
1 元宇宙的定义
本质：1?? the next generation of internet, 2?? the convergence of physical world and virtual world
世界：虚拟世界和实体世界同步（实时渲染），且虚拟世界是3D的，你的虚拟世界中的角色地点行为特征会随着你在真实生活中的变化而改变，且我们可以和虚拟世界交互
容量：1??足够大，无限人物、物品、场景（要求云服务能力、芯片算力等技术），2??时间上是连续的
问：今天我们所见的VR电影、游戏中的明星音乐会是元世界吗？
答：不是，元世界要求同步、连续、无限场景、无限人数，上述两个案例均不满足，不是元世界。VR头盔只是硬件，只是metaverse的入口（access）。目前元世界到来的技术尚未ready，元世界真正到来的时候，或许在十年之后
2 元宇宙的可能应用场景
不用带电脑了，互联网surround us everywhere
3 元宇宙的一些重要术语
MR (Mixed Reality)
特点是：虚拟 & 交互逻辑（现实–> 虚拟全息）
e.g. Microsoft’s Hololens is a well-known example of an existing, commercially available Mixed Reality device. It is a holographic computer you wear around your head, with lenses over your eyes that project holograms you can manipulate and interact with as though they existed in your physical surroundings.
VR (Virtual Reality)
Virtual reality (VR) is a simulated experience that can be similar to or completely different from the real world.
特点：完全虚拟
AR (Augmented Reality)
Augmented reality (AR) is an interactive experience of a real-world environment where the objects that reside in the real world are enhanced by computer-generated perceptual information.
特点：现实+虚拟
e.g. Snapchat lenses and the game Pokemon Go.
Digital Twins
first proposed by NASA in 2010
A digital twin is a digital representation of a physical object, process or service. A digital twin can be a digital replica of an object in the physical world, such as a jet engine or wind farms, or even larger items such as buildings or even whole cities.
In short, creating one can allow the enhancement of strategic technology trends, prevent costly failures in physical objects and also, by using advanced analytical, monitoring and predictive capabilities, test processes and services.
e.g. BMW virtual factory
参考资料：
- Interactive Entertainment, “Going Outside is Highly Overrated”: Metaverse Primer. Jefferies. Sept. 2021
- Wikipedia