What resolution is each texture map?
VMOD 3D Library creates its Digital Fabric resources using the Vizoo scanner.
When the fabric is scanned by Vizoo, it is saved at a very high resolution of 7397x 5289 pixels, which is close to 8K.
Then, in order to provide a seamless texture map, we carefully crop the optimal repeatable areas from the scanned image. Please note that there is no loss of image quality when cropping from a nearly 8K image.
Therefore, even if the PBR texture map is smaller than 4K, you can see a clear image as the resolution is very high.
To convert your PBR maps to 4K, simply repeat the maps until the pixel count reaches close to 4,000 pixels. See the image below: