AMD has launched the GPU Open MaterialX library, a new online library of free downloadable materials in the open-source MaterialX format.
The firm describes the library as providing “ready-to-use PBR materials aimed at jumpstarting the creative process and rendering workflow for 3D graphic designers and game developers”.
The library currently contains over 290 materials, including architectural staples like tiles, flooring, brick walls, plaster and concrete, plus metal, wood and fabrics.
Nice! Thanks for the info.
Ok… so everyone needs to have their own version apparently:
Feels a bit like this, doesn’t it?
Does anyone ever use these for anything, apart from corporate PR?
Just to be clear you’re comparing an open standard with backing from many studios and software vendors (materialx)
To mdl which is mainly supported and promoted by a company which is fairly well known for keeping things proprietary?
And calling them competing standards?
Furthermore I should note that you can output mdl from materialx but not the other way around. I know people love to use xkcd references but I don’t think that applies here. AMD did not invent materialx we are just promoting the open ecosystem.
Are those materialx materials in that library fully procedural or based on tileable bitmaps (most likely created in substance designer)? I know there are some procedural noises and low level nodes in the materialx spec, but I don’t know how far they can be pushed.
Mostly pbr bitmaps for now. But the noises in materialx are pretty good
Can anyone explain how we open these MaterialX files with mtlx file extension?
I do not see an importer in Blender.
You can use this addon from AMD.
This release was a bit buggy for me, it was constantly freezing however this is the way to work with materialX and USD in Blender for now.
Thanks, this is what I was looking for.
The library looks nice, but it looks like the add-on isn’t available for MacOS. 
I can still d/l the files though, so I can use the PNG textures just fine. (They also provide links back to Polyhaven — where available— and their .blend files, which is convenient.)
PNGs for things like Base Color aren’t always included, but in those cases I can open the .mtlx file and pull all kinds of info out of there. It takes a few extra steps, and there are some nodes that I can’t figure out — yet — but it’s still a nice resource. 
For various reasons Blender on MacOS doesn’t currently allow loading USD libraries which the add-on has.
