I came across this on outsapop, and yeah, says it all really.
However, I’d just like to expound on my personal philosophy on the subtle differences between inspiration and copying, and a further explanation on my label “own design” that I use from time to time.
I am inspired all the time by so much around me, including the work of great and talented designers and am often moved to create something for myself based on someone else’s idea.  However, the end result is often, if not always, very different from my original source of inspiration, perhaps because of some design whim of my own, or a personal colour/length preference, or to fit a quirky design detail within the practical considerations of my life.  In this case I consider myself to be “inspired” by another’s work, rather than for me to be “copying” another’s work.  It’s very rare that I set out to reproduce a piece exactly, and I’ll always reference my inspirations! some small consideration to intellectual property!
I do use commercial patterns, for basic shaping and sizing, but a lot of the time will add my own twist to a pattern.  Altering a hemline, neckline or incorporating fitting features are just part and parcel of basic dressmaking variations; but anything more complicated than this and I will start to consider added features as my own design, and I’ll label it as such, even though I always display my original starter pattern for reference.
As for the self-imposed fear that the home seamstress often has of “ripping off” designer items….
Take a basic blazer.  Who invented the blazer?  Let’s even take it a step further and narrow it down to a military blazer.  It’s been around since Civil war era and I’m pretty sure no-one knows who actually invented the thing, but it definitely wasn’t Balmain and yet I see fashion editorials devoted to the horror of “Balmain copies”…. please, it’s a trend, not owned by anyone, and free for the home seamstress to play with as much as she/he fancies.
I say if you want to take a piece of cloth, make your own sharp shouldered jacket and put a few brass buttons and epaullettes on, then yay for you!  You made yourself a blazer!  You win!
On a related note, true story: a few years ago I made myself a ball dress that I spattered all over with fabric paint and told a friend that I got the idea from a Dolce and Gabbana gown.  He asked if I was worried about getting sued.  Seriously.
What are other’s opinions on this point?