Lights HDR render settings in Houdini

這是一個簡單的基礎介紹教程，教程主要是以下內容：

How to make a houdini area light behave like a vray light Using environment lights Using HDRs for lighting and reflections Understanding the render parameters of Mantra PBR to get a clean render And finally modifying HDRs using COPS and then using them in the environment lights.