Clouds are a great example of volumetric shapes. They're gaseous which means they can't realistically be modeled with polygons. Instead they're entirely generated with shader nodes. To watch the full course, head to CG Cookie ☁️ https://bit.ly/3eOQUR5 Even though volumes require notoriously long render times with Cycles, Eevee makes volume rendering practical. Thanks to Blender’s cutting edge Eevee render engine we can generate, tweak, and perfect cloud volumes in basically real time. | CG Cooki

Clouds Tutorial for Blender Cycles