After about a year of working on and off on this project, it's finally complete enough for me to release it.

It's easy to make an AI spartan using the MasterChief's animation set, but this mod goes above and beyond. With a custom animation set designed for AI control. It includes animations for every rifle, pistol, launcher, and turret. As well as animations for every vehicle the marines can operate (including pelican driver seats, scorpion passenger seats, and transport warthog seats.) As well as cover animations for corners and low cover, gesture animations like pointing, transition animations when going from standing to running, or standing to crouching etc. As well as climbing and diving animations.

Most animations are ported from the spartans_ai tag from Halo Reach. But touched up to fit the Halo 3 spartan, and modified to blend into other animations better.

A custom spartan model had to be created to accommodate all this, as the default Halo 3 spartan model lacks a physics_control node in their skeleton, which is required for some environment animations like climbing or taking cover. The new models provided are identical to the original, They just have a physics_control node added.

Meaning, that if you wish to use these animations on a custom character model that uses MasterChef's skeleton, all you'll have to do is add a physics_control node to the base of the skeleton to make them compatible.

What's included?

masterchief_ai.biped
(A custom biped for MasterChief designed around AI control)
masterchief_ai.collision_model
(a modified collision model to accommodate the new render model)
masterchief_ai.model
(the tag that pulls everything together)
masterchief_ai.model_animation_graph
(the custom animation set, and the largest file in the download)
masterchief_ai.physics_model
(a modified physics model to accommodate the new render model)
masterchief_ai.render_model
(a modified model of the MasterChief with a physics_control node added)

ai folder
spartan.style
(a reference tag specifying everything the AI is capable of)
masterchief.character
(an AI tag for the MasterChief)
spartan_generic.character
(an AI tag that utilises the multiplayer spartan model, configured with it's legacy permutations)
gen2.character
(an AI tag that utilises the multiplayer spartan model, configured with the new halo online permutations)

cinematics folder
(just the modified animation graph used in the cutscenes of the showcase mission. Not required at all, but I though I'd leave it in here)

damage_effects folder
ai_dash_melee.damage_effect
(a custom damage_effect tag for the spartan's melee. It's based of the some one used in Halo reach)

spartan_ai folder
spartan_ai.render_model
(a modifed model of the Multiplayer Spartan with a physics_control node added)
spartan_ai.model
(the tag that pulls the spartan_ai together)
spartan_ai.biped
(A custom biped for the multiplayer spartan designed around AI control)
shaders folder
mp_personal_decals.shader_decal
(this is a copy of the multiplayer spartan's mp_personal_decals.shader_decal. It's identical, and only here so that the correct shader is used when compiling. As tool defaults to the multiplayer elite's mp_personal_decals.shader_decal)

I've also uploaded all the data files I made. Meaning, if you wish to add more animations to this mod, feel free to do so. everything's there, so you can recompile the animation graph whenever, without having to resort to animation inheritance.

I also purposely avoided reusing animations wherever possible, so that way I wouldn't have to edit the animation modes every time I made an edit. But there are 2 exceptions.
1: All the scorpion passenger animations are the same. So I just made 1 mode "scorpion_p_lb" and duplicated it for the other 3 seats.
2: I copied the "unarmed" block in the "patrol" mode and pasted it into the "combat" block. giving the spartan some animations if they lack a weapon.