Pro Tip: Don't Forget Standard Textures When You Use PBR Materials

[Cristiano]

Something I completely forgot about, and is not particularly intuitive, is that you need to provide textures for non-PBR viewers, but you cannot do so after you have applied a material without removing it first. Make sure you apply your standard texture to the object first, then switch to using pbr and apply the material. Older viewers will see the standard textures, pbr will use the material. If you forget this step, the user in non-pbr viewers sees the default plywood texture. To remove a material, just click on the material in the object's texture tab and select None from the popup.