Left 4 Dead 2 Style Wound System Complete (Mostly)

Great news!

The Left 4 Dead 2 style wound and dismemberment system mentioned previously, which will be powering the gruesome world of Dungeon Survival, has now been completed (save for a couple of odds and ends, and art assets).

Previous screenshots were taken using a hacky method of transforming the hit location into mesh-relative coordinates, whereas the proper way of doing it, and really the only way that truly works, is to use the “pre-skin” vertex positions.

For non-developers this essentially means getting at the points that make up the character mesh before they’re transformed by the animation rig.

The effect of this is that the opacity-mask sphere which creates the “hole” in the character mesh so that the wound geometry shows through will follow along with any animation properly.

This meant diving into the guts of Unreal Engine 4’s material system, right down into the proto-shader files that underlie familiar visual node-based materials. Luckily this ended up being quite painless!

Remaining work to be done on the wound system itself is to use a blood mask to dirty-up the edges of the character mesh where it’s hidden by the wound-ellipse.

Other than that, all that remains is to create wound meshes for the characters and hook up and tune the system.

As an aside, I decided to work on this today because work on motion controller IK has stopped for the moment while the new full-body IK with limits plugin is debugged a bit by its author for my use case.

I can’t wait to show off some of the gameplay with the new full body IK and motion controls, as it’s something you don’t often see outside of triple-A games that use software like Havok Behavior or Autodesk HumanIK, and is perfectly suited to VR avatareneering..

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