I seen this happen before many times in Halo Custom Edition modding. For example, a guy would take a reach shotguns model and rig it with the already available halo 3 shotgun animations and BOOM: cool looking halo reach shotgun with halo 3 animations or an elite minor from halo reach and rig it with the already available halo 2 elite animations and BOOM: cool lookin halo reach elite minor with halo 2 elite animations. I also seen this happen with halo 3 as well: the star wars mod in sandbox. I saw one of those pretzel kind of looking vehicles that are used by battle droids on geonosis (Dont know what its called) rigged to warthog animations alongside with a lightsaber rigged to energy sword animations and a laser pistol rigged to magnum animations. And again I saw this before with Halo online videos of people replacing spartan helmets with shrek heads.
honestly I have no experience with rigging models in Halo Custom Edition because 3dsmax's user interface or any other 3d modeling program's UI IMO is extremely complicated but I do know how it works(Correct me if Im wrong).
For preparation, load up some halo biped/weapon model with its corresponding textures and shaders. (Next bit is a little wordy I'll try my best to fully express the corresponding steps) Delete that model's bone structure and import the new bone structure from the model that has your wanted animations???(For example, load hr hunter with textures and shaders. delete its bone structure. import ONLY the bone structure from the halo 3 hunter model) Manually adjust the bone structures to its corresponding meshes. (For example, you have an elite minor from halo reach with its bone structure deleted. Then you've imported the bone structure from a halo 3 elite model. Knowing there was a significant art style change in elites progressing from halo 3 to halo reach, you would adjust the bones to the mesh such as moving the halo 3 elite arm bone towards the halo reach elite models arm mesh and so on and so forth till the bone rigging is complete). Test the completed model with animations from the model of the new bone structure you've imported.(Play a "strafe_right" animation from a halo 3 elite on your completed reach elite model with halo 3 elite bones) After all of that messy work, finish it off with tagging.
I don't know if there's other ways to do this but the one above is the only method I know of.
Just wondering if this is possible with current xbox halo modding tools such as assembly or adjutant. I want to adjust halo to my liking in terms of the look and gameplay. FYI I do not have an rgh xbox but my friend is giving me his rgh within a week. I do have one and a half years of mediocre modding experience with mainly Halo custom edition and a tiny bit of minecraft. (I mainly used programs to mod. I have been in a couple java coding classes in the summer. I do know how games work and I kind of know how to code(I can make simple calculator programs) I also can get an easy understanding the code structure of some file)) Im just wondering how a guy made a star wars halo mod with custom models rigged to vanilla halo animations and how gamecheat13 managed to create his own bsp shown in his AI playground and his other old halo 3 test maps(I do suppose gamecheat created it using math. after all the bsp is just a simple cube)