If you want to give your PC a different form (say, of a mountain lion), I heard that one way is to 'paste' the mesh over the PC through use of a clothing object. How would this work? Do I just create a new clothing object and set the character model to the mountain lion mesh? That seems to be the obvious way, but what about all of the animations, and such?

Thanks

Okay, so far I've been able to ascertain that first, I have to stitch all of the mountain lion 'pieces' together in nifskope before I can 'wear' it. But that still doesn't explain how the animations will work. I got the idea from http://www.uesp.net/wiki/Tes3Mod:Form_Change#Form_Clothing, but that doesn't explain how to do it. All it says is:

I have no idea how to do any of this, as I don't know what defines a 'useable model'.

Can anybody help me with this?

You can't do that. An actor model (as well as armor, clothing and anything else that the actor may equip) is rigged to a 'skeleton' - a bunch of connected nodes that have roughly the shape of the actor. This skeleton is animated and the model on top of it moves with the skeleton animations. Each type of actor has his own skeleton. Obviously you can't rig something that has the shape of a lion to a skeleton that has the shape of a human.

Then how do so many mods include shape-changing, and why do so many people recommend clothing objects?

i know of one technique to do this (though it isnt the best).

The player is turned invisible and a creature is placed in their spot instead. Using key detection this creature is then controlled as if it is the player. Its not very effective though...Im sure there is a better way.

Shape changing from one shape to a completely different shape is always done by script. I think what da mage posted is the way how it's done. IIRC in Midas Magic the white tiger is a ridable creature. The player sits on top, but is invisible. You only see the tiger, even though the player is still there. And you can move the tiger without any additional scripts. Attack damage is done with a triggerzone in front of the tiger's mouth.

Clothing objects can be used, but only if the shape fits the skeleton. A Frost Atronach for example is possible, since the shape is roughly that of a human (there is a mod that adds a bodysuit like that on Nexus). A lich, a Xivilai, all possible. A mountain lion is not possible unless you make it stand on two legs, have arms and the like. Basically what a Khajiit is.

Yeah, I heard of that. It seems like an easy alternative if all else fails. However, when the player moves, wouldn't the creature taking their place just 'float' around?

I guess that's why the "mount and become invisible"-approach is the more common one. The creature moves when its "rider" tells it to move, just like when riding a horse.

Ah, yes. It all makes sense now. I suppose I'll use clothing for humanoid creatures and I'll look at the wiki for making the rideable creatures.

You could place a script on the clothing, so that when it is equipped the player "mounts and becomes invisible".

Midas Magic has spells each using the aforementioned techniques.

Polymorph Weretiger puts a "costume" on the player. Looks rather like a sports mascot

Polymorph Eagle & Wolf make the player an invisible rider on these animals with the trigger zones mentioned.