Yes, have bug report to e-mail (hikmetkoyuncuproducts@gmail.com).

No, but we strongly recommend you, because this will make it very easy to use. But if you don't want install add-ons, then you can easily link or append materials to in your scene.

You can find this information at the Installation Guide.

Not all of them. As of this writing, there are just some details that procedural textures couldn't achieve yet via Cycles or Eevee nodes, that's why we decided to use Image Textures instead which are in most cases, faster to render and more manageable. But the VMATS has been created to have a good balance of procedural textures and image textures.

No. But you can use textures in other programs/rendering engines. If you have the technical knowledge on translating the existing shaders into compatible materials in your software, that would be better.

You need to close preview image window/program after open any preview image. If you are not close this image, then Blender waits until close this preview image.

Some materials require you to have a UV map to function optimally. To fix this, select your model, go to Edit Mode, and create unwrap your mesh.

Yes. All textures in VMATS are seamless and tileable.

To balance out quality and efficiency, we decided to have the textures' size at 2K (2048 x 2048) by default. This ensures that you will have a scene that your system can handle and you have large enough textures that are not pixelized even at closeup renders. If you want 4K (4096 x 4096) textures, ALL of the materials have 4K texture and you can download 4K Texture Pack on product page and use these.

We believe in empowering the Blender community of artists and this is our way of making it accessible to everyone - students and professionals alike.

Absolutely! You're free to do this as long as you don't sell and/or redistribute the materials in the raw format and claim exclusive ownership.

VMATS for Cycles contains 1819 materials, VMATS for Eevee contains 1755 materials. VMATS totally contains 3574 materials.

For professionals, time is money. Creating a realistic material generally too hard and time consuming. An average scene has many objects, and each object has at least one material. When we start create materials for all of this objects, this takes much much more time. When you have to repeat this action for every scene, every time you need to waste your time. And time is money.

For amateurs, I think there are master artists who are great at creating materials! I can not understand how they do it. But I want to create great materials and great scenes too. How can I do? I wish there were quality and realistic materials such as these that were ready-made. In this way, I could produce quality scenes like them.