[Tutorial Preview] Gore Mesh & Dismemberment Tutorial

[n00854180t]

@Chosker;572413

yeah that would work.
these proxies, are they also having ragdoll, or how would it look for example a cut arm?

It’s not anything special - just a copy of the complete regular (no special art preparation) character mesh. The only thing is that you need to set a special physics asset up for the proxy depending on which part of the body it will be representing (e.g., so if it’s the arm + hand, you’d make it so only those bodies are in the physics asset).

1. the code itself is what I described earlier: it modifies the vertex weight data at runtime to swap it with the ‘broken’ version of it.
   as for the assets, UDK has an unbroken mesh and a broken one, stored in the same mesh asset (internally it’s probably just a diff list of those vertices that have different weights). as it keeps track of which vertices are associated with which bone, it allows partial swapping (i.e. you can cut an arm at the torso and the other arm will be fine).
   the user had to hide no geometry seams because the bodypart-adjacent vertices are skinned exactly the same (the issues from the screenshot didn’t occur). the only seams came from vertex normal discrepancies and that was only because UDK’s FBX import of SkelMeshes didn’t support custom vertex normals (hope it’s supported in UE4).
   then again vertex normal seams are common in games with paperdolling, like in Skyrim.

Hmmm alright, that’s sort of what I suspected - the problem for me is that I suspect making all that work would take a lot of time since it’s going to mean digging into potentially both FBX stuff and the SkeletalMesh class itself.

That said, I’m still interested in getting it going as it’s sorely needed for many games. I just don’t know how much time I can devote to it vs just using the quick and dirty method I have. If any other programmers reading the thread are interested, let me know so we can work together on it.

2. I have my own art from my UDK game, where I fully use dismemberment. I can provide you with this but only for private testing.

Of course, I absolutely only meant for private testing to get the functionality working.

3. for me the pipeline is easier than having to do “pre cut” versions of every body part to use as proxies.

The system I have doesn’t require you to pre-cut anything, which is the main thing I wanted out of it. That said, it does require some in-engine preparation, e.g., to place the cut and set up the proxy to be right for a given cut.

the requirement is that your meshes need to be separated into detached sub-objects, so that the cut can be clean.
the other hard requirement is that the broken and unbroken meshes need to have exactly the same amount of vertices/faces, as the swapping is done 1:1 using the vertex indices.
usually they should also have “stumps” to avoid holes, already as part of the original mesh, but you wouldn’t need them if you do the l4d-style hole filling.
for me it works like this: for every mesh that can be cut, I make a copy in my 3d software. then I modify the weighting of the vertices at the cutting zones so they only belong to one or the other bone. export, done. for me it’s like 3 minutes per mesh but I’m used to the workflow.

I myself would stay away from anything that modifies the engine source or the shaders.

I can provide you with some source art. but actually I’d just do it with the unreal mannequin so you could provide it as an example if you release the code.
but only if you’re convinced that the workflow would suit you

I’ll look into the code and see if I can determine how much work it would be to add the functionality.

Sadly, I don’t know if it’s really possible to do as a plugin, but I’ll investigate and see.