Instructions:

1. Start your scene however you like.

2. Append the 'pottery' material from pottery_shader.blend into your scene.

3. Enjoy :D

For the addon:

1. Go into Edit->Preferences->Add-ons->"Intall from file..."

2. Select the materialDuplicator.py

3. Now inside the Node Editor, on the properties panel should be a "Duplicate" tab

4. Clicking the "Duplicate Material" button will make a copy of the current material using the correct references for the drivers.

(This is only temporary until this behaviour is fixed on future blender releases)

In here I will explain and describe what the different sliders do so that you can start using the shader right away:

• Main Color: The main color of the material.
• Gradient Color (Middle|Bottom): This two inputs control the color of the object each of them correspond to a point of a gradient that is used to define the patterns. When the 'Pattern Amount' is set to 0 the Main Color is used.
• Detail Color (Small|Large): This tow options control the color for the detail for each specific scale.
• Detail options (Scale|Sharpness|Amount|Randomness): Both Detail levels contain some options to get them to look exactly how you want it. Scale controls how big each detail level looks. Sharpness control how sharp the imperfections are (like the difference between a small bump and a hole). Amount controls how much of the detail gets through. And finally randomness affects how random the imperfections are (if 0 it looks sort of like a grid).
• Pattern Amount: If disabled (0) the the overall color will be uniform, as you start to increase the value, a gradient will appear using the colors set on the options above.
• Pattern Distortion: controls the "warpiness" of the pattern. If set to 0 the pattern will resemble rings and as you increase it the rings get more and more distorted.
• Pattern Scale: controls the scale of the pattern.
• Pattern contrast: controls the contrast between the color of the gradient.
• Metallic: If you wish to make the object metallic then go for it!
• Roughness: overall roughness of the material.
• Clearcoat: clearcoat amount.
• Clearcoat Roughness: the roughness of the clearcoat.
• Normal Strength: the overall strength of the normals.
• Imperfections Normal Strength: controls the normal values of the surface details that you can set with the options above.
• Normal: add you own normal map on top of the imperfections that are automatically created.
• Clearcoat Normal Strength: the overall strength of the normals for the clearcoat.
• Clearcoat Distortions: controls the normal values of the surface distortions that are automatically created using the pattern design.
• Clearcoat Normal: add you own normal map for the clearcoat on top of the distortions that are automatically created.

NOTE / DISCLAIMER: The are some know limitations when it comes to using procedural textures as normal maps in EEVEE that may cause some slowdown when previewing it, this does not affect render times, its just the preview that gets slowed down when looking to close at the material.