/3/ - 3DCG

>>689013
Marvelous designer.
Though there's a few ways to do it in Blender too. None of which is really all that great.

You could model the costume like a normal mesh, then apply the cloth modifier.

Another option is to do it similar to how MD approaches clothing, and use actual clothing/sewing patterns. Basically you'd model out different sections of the pattern, and arrange them in roughly the right position (left side of pic related).
Make all of it one mesh, then connect the areas you need to sew together with edges (not faces). Start up a cloth sim, turn the gravity influence kind of low to start off, and make the sewing strength nonzero. When you sim, the edges that you placed will draw together. Once everything is "sewn", turn up the gravity during the sim, and let the cloth fall down. Have collision enabled on the model you want the clothes to be on (preferably a lower poly version to speed everything up).
Should everything go right (it won't) and you've got your settings and stuff good, you'll have a piece of clothing. If not, and chances are nothing will work right, be prepared to spend hours fucking around with it until you get things right, have it fall exactly how it needs, fix all clipping problems, and whatever else Blender decides to fuck up during the sim.
Then you'll realize that Blender's sims are fucking ancient, and that MD was built exactly for this, and just buy it or "acquire it". You'll then live happlily ever after when your clothes work first try without any fucking around.

There's Blender addons you can buy that do what I said above but makes things easier, but you're still fucking around with Blender's shitty sims, and that's the real linchpin of the problem that there's no getting away from and why they can't compete with MD. MD was built exclusively for cloth sim, Blender wasn't. There's no getting around it.