n.预置
Because the Particle Volume Cloud shader has many options to set, you can start out with the Particle Renderer or Particle Shaper shader compound to render a volume quickly. 因为粒子体积云阴影组已经预置许多属性，用户可以使用粒子渲染节点或者粒子形状阴影复合节点快速渲染体积。
