Bodyweight training can be referred to as calisthenics, which is a widely popular training methodology that can result in decent muscle mass. It may be a slower progression than traditional weight lifting, but you can certainly build a sizable lean physique.
Your example of Brad Pitt from Fight Club is actually a pretty good example of what can be ...
My experience seems to show that you can't significantly change
anything regarding your physique with solely your body weight, even if
you work out regularly for years. On the other hand, you can find
loads of shredded YouTube individuals arguing that you can build your
muscles effectively with nothing but your body weight.
Where's the truth?
This was the point of Charles Atlas' Dynamic Tension workout. He was too poor to own any exercise equipment, or join a gym so he developed (with some borrowed ideas) a system of muscle building using muscle-vs-muscle resistance.
My experience seems to show that you can't significantly change anything regarding your physique with solely your body weight, even if you work out regularly for years.
You can absolutely change your physique and put on muscle mass using only bodyweight. This area of working out is called callisthenics. One of my favourite callisthenics YouTubers is Chris ...
If you look at the basics you'll see that you don't need weight, you need resistance.
The most common way of finding resistance is by using weight because you can increase it in steps, making progressive overload easily achievable. But you can also work without weights and find increasingly harder exercises rather than making the same exercise harder.
A simplified answer - yes.
It depends on any secondary goals you have too, do you want to achieve immense strength in any specific movement, learn a skill (handstand, front lever, etc.), obtain a certain type of physique, improve your overall fitness level, etc. If you do have them, it’s good to train movements specific to your goal. There are articles ...