A question about rigging

It recently occured to me that rigging for scratch-made animations and that for already existant ones is different in some way... Can someone with more knowledge in this domain please explain in what way are they different exactly?

When you're rigging to set up for a transfer of existing animations, you need to name your bones after the ones in the animation-containing model.

And that means you need to have the same exact number, placement and names of bones?

With scratch-made animations, you can rig the skeleton as you would prefer for your own ease of work.

With transference, you are governed by what is already present, as Guesst said.

The placement has to be roughly similar. For bones that you want to transfer to each other, the names have to match. That is all.

Sounds like a lot of work, is there a way to export the bones from one, slap them onto the other?

I have an awkward and slightly cack-handed method of getting the rough skeleton out and into Milkshape, but I suspect that's of no use to you.

And even after that, you have to rearrange the matrices in the final MDL (not so hard as it sounds, since the Guesstsporter comments what bones the matrices point to on export).

The bones don't technically have to be in the same positions etc for my method; since all that matters is that the geometry is assigned correctly, and it is then ported onto the target model. They're just nice to have so you can design your new model around the correct pivots to make sure it'll look nice around the edges.