How to make an inflatable object?

I have seen someone make a inflatable heat pad that gave the full effect it’s called LOFTid, you can find it by using that one word, tho types of air or air temp or pressure can’t provide life

Ok thank you

Well you can’t! You could sort of reproduce the effect using pistons. The idea being you have fuel tanks the size of the inflated object and hid them (or reduce their size by having them clip together) then use pistons to “expand” them out.