When you build something, taking raw materials from their current state and assembling them into something like a car or rocket ship, is that the opposite of entropy?
not really. what you're doing is using an external energy source to locally order things at the expense of increasing global disorder (ultimately contributing to the heat death of the universe). some people will use a term https://en.wikipedia.org/wiki/Negentropy to refer to this process.
That's my point. Saying engineering is the opposite of entropy doesn't make sense to me.