Hello ! 
( Sorry for my english mistakes ! I’m french ! )
A question about animations and in particulary the managing of collisions during combat scenes in a 3D game. I’d like to know if Unity is capable to manage collisions of “weapons versus weapons”. Typically : a sword who hits another sword or a shield, for example… I suppose that it’s possible even though I don’t know how it works exactly. Can the concept of ragdoll apply itself to an object attached to the rig like a sword or a shield ? Is it managed with a box collider ? I don’t know. I’m a total newbie in Unity. I know a little the main basic principles of the software. I’ve got some notions of computer programming. But that’s where it ends.
I’ve research on internet some videos or tutorials who could enlighten me but I haven’t find exactly what I want. I ran in particular into this video rather impressive of realism of an asset of animations of melee combat :
Basically, I’d like to see the same kind of video but with collisions of weapons versus weapons. Is it possible ? And above all, what could it look like ? Is it clean (no weapons who go in all directions, no glitch, etc…) ? Would you got some video examples of what I’m searching ?
Thank you so much !
Yep. You answered part of your question already. 
You can do that stuff, by using box colliders, capsule colliders etc.
together with rigidbodies.
Or, if you’re skilled enough, you can the same thing demonstrated in the vid
using triggers, together with animations too.
Eg. Let’s pretend, you have 2 fighters.
We shall call them Player 1, and Player 2.
And Player 2, has a trigger on his left leg, with a fall down animation,
connected to it.
If Player 1, punches/kicks, Player 2, on his left leg (which has a trigger on it)
the fall down animation is activated. And you’ll see Player 2, fall down to the ground.
But this technique, requires some clever thinking, and a good bit of imagination
too. And can also be applied, to sword fighting characters too.
Yes, I’m sure you could do it, but I think it’d be more beneficial to determine how other games handle this type of action. Very very few games rely on actual collision to check for blocks/parries… Swords and shields tend to be small objects that move very quickly, this causes problems because they can pass straight through each other without ever actually colliding (since time is discrete.) Most games rely on distance, direction, and state only to determine these types of things. For example, I’d be willing to be a very large sum that in the Breath of the Wild source code, Link’s sword is anything other than aesthetic and damage and missing is part of his character code.
There have been examples of using real collisions and physics, but they tend to be very clunky. There was a tech demo called “Clang” that was this. The dev eventually realized that the idea was really cool, but it did not make good gameplay.
