Best method for creating tiling pattern?

[JonnyS]

I’m working on fabric pattern designs to be printed. I’m having a very hard time finding a way to accurately create a tiling pattern which is usually done by bisecting the image horizontally and vertically and rearranging the tiles in a manner that  makes the image tile or continue on if it were printed onto a long run of fabric. It’s crucial that the image be exact or there will be a line in the design on the fabric which can be extremely problematic! The. 2 issues i’m Having is that 1) if I use the marquee square tool on a specific layer, and say try to copy or cut that section. it still applies to the whole image as if the marquee was not giving the command a boarder. The other is that it’s difficult to accurately cut the image in half because the guides and magnets only work when you’re moving images or things of that nature.  Any quick and accurate (or long and accurate at this point!)  tips or processes would be greatly appreciated! 

 

Thank you friends!

[DM1]

I found a vid on utube explaining how to achieve this with symbols. You create multiple artboards and use one as the design, which you add as a symbol, then paste the symbol onto other artboards. You need to look at a vid to really understand. Attached is a sample I set up to repeat a simple pattern. The layer I marked with colour is the main design. Any changes you make to that are replicated across the design. If I find the vid link I’ll post it here. Meantime have a play with the attached file and you will see how it works. 
 

Here is the video link 

 

Repeating pattern.afdesign