Sometimes tiled textures are not provided or are not yet available. In these cases, it can be necessary to create your own textures from existing reference images.

• Choose a appropriate area of your reference image to use as a base. The section should be clear, with no blurriness and no harsh differences in lighting.
• Cut it out to your preferred format. For most cases, this will be square. In Gimp, this can be done with the 'crop tool' or the shortcut shift + C. The desired size can be further adjusted In the tool options.

• Click 'Filters' → 'Map' → 'Tile Seamless'. Your texture is now tileable.
• Adjust the resolution as needed.

• Click on 'Layer' → 'Transform' → 'Offset'
• Click 'By width/2, height/2' and confirm with 'OK'

• Select the 'Clone' tool (shortcut 'C') and choose a soft brush
• Press Ctrl + LMB to select a source area around the seam that is similar to the one you want to blend it with.
• The selected source area will move proportionally to your mouse, so you will have to alternate between selecting a source and blending the seam.
• Repeat until all seams are blended and you are happy with the result.
• Adjust the resolution as needed.

• Click 'Filters' → 'Map' → 'Tile' and set the size to be a couple of times larger than your texture.
• This will create a new image which you can use to check the seamlessness.
• The example shows a 2667×2667 texture tiled in a Canvas size of 8001×5334

• Again, cut out a part of your reference image in the format you want your texture to be tileable in.
• Head to this website https://www.imgonline.com.ua/eng/make-seamless-texture.php
• Upload your cut out part and adjust the settings to your liking.
• Click 'OK'
• You can now view and download the generated texture.
• The site has a built-in option to tile the texture, where you can check the seamlessness.