I make all of my patterns on Adobe Illustrator. I never use commercial patterns/textures, except for a woodgrain one and a 'cotton' looking one. The surface embellishment (text, texture) is so integral to my pieces that thinking that they could simply be duplicated by anyone with the same texture sheet is not appealing to me. I consider the patterns to be the art of the piece, while the construction is the craft.
I'm currently working on creating a pleasing 'starburst filigree-ish' type of pattern. Above is what my Illustrator screen looked like in the initial stages of the new designs....it will get much messier as time goes on. The next steps will involve freehand patterns that I will either draw on my tablet, or draw the old school way and scan in. I complete all patterns with Illustrator because even if they are scanned in, I can then manipulate the image, resizing the line widths and shapes to suit what I'm doing.
Best part is, the computer stuff all happens during Young and the Restless hour.....actually, during any TV watching. I find it a little bit difficult to just watch something without doing something with my hands....I guess it's my version of knitting.
Often, I will make a quick printing plate and test it out on polymer clay. This way I can place other findings with it and see about spacing, etc., and see if I'm on the right track before I spend a lot more time on the embellishments of the Pattern.