After playing Dead Space I want to know which ways exist, to destroy objects and dismember creatures.
And no, I don´t want to make Dead Space...
I know some ways, but I don´t understand the technical side of some of them.

Quake II made it with simple animation\replacement of the Model, so that the injuries were predefined.
Disadvantage: you shoot the legs and the head of the enforcer disappears... strange. So I don´t want to use this for my project.

Turok 2 had one centerentity with attached limbs, with the limbs having own hitboxes.
If the limb was hit, it was removed and the centerentity reacted to it.
This was not bad, but the disadvantage was, that it was
clearly visible, that the Models were attached.
They had ugly seams. With machines there is no problem, because they are assembled,
but for living creatures this is not, what I want to achieve.

Then Dead Space has seamless models with fixed points, where they can be dismembered.
The same thing for Mortal Kombat 2011. There is absolutly no visible hint, that there is anything removeable...
Something similar I would like to use, even if that is still not perfect.
But I have no clue, how this has been done.
This seamless-thing is, what is most important to me, to have the models look consistent.

Then I read about a Metal Gear game, I dont know the title,
where a guy with a sword is (or will be) the main protagonist, and they wrote,
that it is possible in the game, to cut ANYTHING that is destroyable in the world DYNAMICALLY.
The way he slashes is the exact way the blade cuts.
I imagine it like the slice plane in the WED editor for cutting blocks.
If it is true, how could this be achieved?
I think there is a huge lot of calculating going on there...
That would be my favorite (of course) but I don´t think, that could be realistic to be achieved by me.

Anyone knows how that all works?
Do you know any other additional ways used?

have a model that has several versions that get swapped out based on what part of the model is hit. it will take up a lot of space if you have vertex anims, but will look fairly reallistic without a large amount of dynamic calculation.

Maybe you'll find this interesting.

Fair warning: There's some imagery in there that may not be for everyone. Depending on your love for blood and gore.

neat paper, thanks Error!

I think FULLY dynamic dismembering (that you can cut off 'things' at any position) isn't possible with 3DGS. But I've got two ideas. I don't know
if it works but you can try it:

1: You can use different skins together with the OVERLAY-flag (which makes every black (0,0,0) pixel transparent). 'just' change the
skin to another, where everything which shouldn't be visible is black.

2: The same method - but using a shader and a mask instead of different skins. A bit complicated if you don't know much about shaders, but it would be possible to make any combination of areas invisible with only using 2 skins (it would be also possible with one).

You could also use vmask to hide certain parts of a model.

I think it's still possible, I know how to put holes in a body via shader, basically using your 2nd way(I've done this sometime ago) but I can't figure how to cap the hole(until I read Error's post). From what I read, valve is using inverted sphere to cap the holes and using normal testing on the main model to decide which part of the sphere's model that should be shown(smart move).

it is, it just takes a lot of fancy math and vertex movement. a lot of work, enough where if i was lonewolfing it or working on a small team, i wouldnt want to try it, there is more important things that will take long enough as is. i'd just have a few varied ways of letting him be dismemebered and leave it at that.

id also guess if you were using a 3rd party physics engine like havok it might be doable through that in some ways, but that kinda integration would also be kinda tough to do as well.

Well... yes, saying that it isn't possible with 3DGS isn't right. Everything is possible in 3DGS.

But it's often a lot of work and everyone who wants to make something really complicated should think about if it is really worth it.

Good.... Reading Valves (very intersting) stuff and some of the posts, I seem to have to restrict myself drastically in damagemodels.
In first place, it was the general technical side of "how did they do that", what had interested me.
And it gave very interesting insights.
And once again it proves, that the simple looking, rather unspectacular effects are the most hardest to achieve.

Now to my desingn-decision (I have not started a project):
Dismemberment\destruction would not be essential or important part of the game.
This would be more or less just eyecandy.
There seem just two possible ways, that I could implement.
But which one should I choose?
This is important, so that I know how to build up my models from the start up.

1. The Turok 2 Way. Attached Limbs on center-entity.
or
2. Create all the different damaged variants of the model and
interchange them based on the areas hit.

I want to use Bones-animation and Ent_Decal. But I suppose that ent_decal will not work with solution #2.
Because I think, when I change the model, the applieed decals disappears together with the exchanged model.