I'm working through Part 6 of "Houdini Is Hip" and I've somehow gotten stuck. He asked us to create a Material Library in the stage and connect it to a SOP Import. Then, we're supposed to create a Principled Shader in the Material Library, but I don't have the option to do that. I can create a Material Network, and then within that created a Principled Shader, but not within a Material Library.

I'd appreciate any help I can get. I'm super excited to see these sparks fly!

Here's the video! [www.youtube.com]

Probably a bit late but here we go. The Material Library itself has a Tab Menu Mask (under Tab menu rollout). This has been changed in the newer houdini to ... apparently.. prevent people from using nodes that don't work together. I personally think that's a rather odd way to fix this issue because you are forced to use material builders for everything which has quite a few drawbacks. If you clear that mask you can create the principled shader again.