by MTKnife » Tue Aug 29, 2017 2:49 am
A good start would be to find files with pictures of cloth (you can find quite a lot of them for free with some web searching). What you're looking for in particular is cloth that can be tiled in a repeating pattern--that means a square or rectangle whose sides are identical to their opposites, so that you can join one side with the other. With real cloth, you might need to stretch or compress one side or the other to get them to line up perfectly--use something like GIMP for that. Another alternative is to create a procedural texture, and then add various touches to make it look like real cloth--there are tutorials on this on the web. You can even find pre-made tileable textures.
Once you've got a texture you can tile, you just repeat it--to do that, you use a "Repeat" node in Cycles, or "Repeat" under "Image Mapping" in the Texture tab in Blender Internal.