Make your blanket a double layer with a tiny bit of space in between, set up a cloth modifier and give it i little bit of self collision. The layers will ‘puff’ away from each other. However, the end result will still be flat, so in addition to having the blanket puff up, model some invisible balls (just turn visibility off in the outliner) and drop them onto the blanket to create small depressions and waves in the material.
what i did on the past tests was putting already made blanket below , i downloaded the free model , and let my blanket falls on to it.
Kinda worked but im still not happy with it… will keep testing until i find a way.
…Have you considered trying out the soft-body sim for this instead of the cloth sim? Thing is that the cloth sim is optimised for planes while the softbody modifier is for things that have volume(like Jelly, skin or puffy blankets). You’ll have to play a lot with the settings though.