Animation Blending

What I’m hoping to achieve:

Shooter style game. Attaching a weapon to a grip point on the skeleton is easy. The gun will move wherever the hand moves at the attached socket. However, the “off-hand” (supporting, non-trigger hand) needs to attach to another socket on the gun so that the off-hand will follow the gun wherever it moves according to that socket and still look fluid. The first solution (and quite frankly the only solution) that comes to mind is to just rig your animations so the off-hand is in the correct position for the needed actions (such as recoil, reloads, switching, etc.)

The problem I see with this solution is not only does it make the amount of animation work crazy and complex but it’s near impossible to be 100% spot on with the animation so there’s no overlapping collisions/clipping. That’s problem 1. Now imagine the amount of animation work that is required for a shooter game that has multiple weapons (not hard to imagine since every shooter game has more than 1 weapon.) Now include that each weapon may have a possible user defined attachment like a Fore-Grip which changes the location and rotation of the off-hand to hold the gun from the new Grip position. We are talking exponential growth in animations for each gun you wish to include in your game. And not only is all this animation a ton of complex work but your game size is growing at a rapid pace. All for sub-par visuals. This also means that you can’t buy animations from the marketplace simply because it wasn’t rigged and animated to fit the gun(s) you are using in your game.

Alright, enough of the ranting on the obvious downsides to this. The main question I am asking, “Is there a better, simpler, and more universal approach to doing this??” I would think it’s along the lines of using the Layered Blend Per Pose node in the AnimGraph but I can’t seem to find any tutorials, tips, videos or docs regarding this issue. Only tuts I can find on Layered Blend Per Pose is about blending from spine_01 so you can blend your walk/run anims with your upper body anims. I’m hoping for more of a ‘free-floating’ type effect that IK’s in relation to the gun position.

Do you know any solutions, videos, docs, tutorials or anything that can help me figure this out? Any and all help on this is greatly appreciated!


Yes, it is, and it’s called Inverse Kinematics (IK for short). On a animation training stream, the team explained how they used it in Fortnite in order to get the hands of the characters (varying size) to grab the weapons normally. Basically it’s moving a bone to a target and affecting all the other bones that need to be moved. Here, take a look:

The same technique is used to aling the legs with the ground (in hills etc)

Thanks for the reply and the link to the docs. Do you know the link to the video you mentioned or know the title of it? Thanks again