Copyright on designs, what it is and how it works
There is a great post about copyright on Poeacock & Fig. Anyway I felt that some people miss the bases of the entire issue.
When designers complain about people sharing their designs, the most common response is "I bought it, I can do whatever I want with it". False.
Let's say a morning you wake up with a big urge to read, go to the library shop, and buy a book. Did you bought the book? Yes. Is the book your? Yes. But, since you bought the book, is the story yours too? No. Neither story, nor the idea, nor the phrases that are written inside the book, that are copyright, and therefore owned, by the author.
What you can do with your book? You can read it one or multiple times, highlight it (please don't do that with library books!), use it as a wedge for a wobbly table, make a personal copy of it if you don't want to highlight the original one, gift it to a friend.
What you can't do with your book? Use the idea or parts of the text to write your own book to sell it, sell photocopies or digital copies of it, scan it and share it with your facebook reading group.
This example works for patterns too. When you buy a pattern, what you have bought is actually a mini-book.
So what I can do with my pattern? You can print it or photocopy it for your own personal use, you can stitch it as many times as you want and you can gift the stitched work to whoever you want.
What I can't do with it? Distribute, sell or share copies of it, or use the design to make your own design to sell.
Can I sell it? In this case, we have to make a difference between hard copies and digital files. If you bought an hard copy or a kit, you can sell it whether you have stitched it or not, exactly like a book. If you bought a digital file, you could sell it only once and you should proof that you don't own any other digital copy of the pattern. As designers (or authors) can not have any control on this, selling digital files is usually forbidden.
The answer is simple and complicated at the same time. The simple one is that law says you just can not as you don't own any right on it. Stop. The complicated one is that someone put his own idea, time, efforts and competences into it, and probably makes his living by selling the final product of that idea, time, efforts and competences. By illegally sharing that product, you are actually stealing a part of his living and you encourage other people to do the same.
In the case of a business company, you're probably stealing multiple persons' livings, or the possibility of the company to employ someone, part of the taxes they pay to the governments, not to talk about their enthusiasm and everything stays behind the mere money.
I can't really explain how frustrating is to find the fruit of much hard work thrown in the illegal downloaders' shark tank. A lot of designers have already decided to retire their design, or to completely stop the designing career. When you decide share a file, please remember that you are hurting, morally and financially, the person who gave you hours of fun, and that may end up with stopping to create things that you like because of you. Think about it twice. Maybe three times. And then don't do it, it's illegal.