Lights HDR render settings in Houdini

这是一个简单的基础介绍教程，教程主要是以下内容：

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.