I'm a Skyrim mod author, primarily an animator. Yesterday, I stumbled upon the strangest thing that I've ever seen in this game.
I'm made some walk/run/sprint animation replacers for a new mod I'm working on. I'm implementing them with DAR keywords. While testing them, I noticed that the arm position during the walk was off as compared to how it looks in Blender. My first inclination was to go back to Blender, check and recheck my keyframes, rebake my animation, re-export it, re-convert it, and try the new one. Same problem. I know for 100% that there's nothing wrong with my animations. The game simply not putting the arms where I told it to.
I began conducting tests to systematically eliminate variables. I tried different combinations of walk and run animations (some made by me, some by others) in DAR custom condition folders, the DAR player character specific folder, and the straight up vanilla animation folder. After some time and much hair being torn out, I discovered something truly bizarre that defies all explanation. Skyrim appears to blend the running animation into the walk somehow. What does that even mean? Well, what I mean is that Skyrim will take whatever running animation it is currently using, and blend that into your current walking animation by about 5% or so, and the resulting mix is the walking animation that will be played. For those who know Blender, it looks as if you took the walk and run animations, dropped both into the NLA as action strips, overlapped them, then put the cursor to where you're seeing a blend of about 95% walk and 5% run. That's what Skyrim plays.
I know--sounds insane, right? It's for real. I tested this again and again with many animations. This occurs with vanilla replacement. This has nothing whatsoever to do with DAR/FNIS/Nemesis. Has anyone else ever noticed this? Am I the first? I've made many animations, but never a walk or run until now. Mostly idle replacers of various kinds. I certainly use walk and run replacers, but I never noticed anything being amiss. I looked again more closely at my preferred walk and run replacers, and it appears that they too blend together, but I never noticed it before because the movement of walking and running is similar enough that blending about 5% of the run into the walk doesn't change it by any noticeable amount. The reason I noticed with my new animations is because the arm positions are very different. My walk has the hands folded behind the back--y'know, like a casual stroll kind of position. I've never seen a position like that before. When blended with the run, the arms move out of their proper position and clip into the middle of the body. When using a walk and run that both have the arms swinging at the sides, the difference from blending in a tiny bit of the run is imperceptible.
I don't know what to make of this, and I kinda feel like I'm losing my mind, but it's true. I can't fathom why Bethesda made it this way, and I reckon that there's absolutely no way to fix it. This must be a hard-coded behavior thing. The only solution for me is painstaking trial and error until I can move the arms into an acceptable position. I can make it work, but I'm just dying to know if I'm the first and only one to stumble unto this strange behavior.