i wonder if the paper mode textures were originally made for sticker star

Yeah, all Paper Jam's paper characters were ported from Sticker Star, with the only changes being things needed for their actions in this game, so there are a lot of Sticker Star leftovers.

so this is just an edited spritesheet from sticker star, i can tell because you can see the sticker book that mario has in that game

clearly you haven't played sticker star

never thought i’d see a flip flop as one of paper mario’s moves. ?

As far as i can tell Paper Mario is handled identically between battle and overworld. I don't think it's that intensive, my personal theory as to why Citra lags so much is just due to not clearing past battles from memory. Paper enemies certainly seem to lag more than non-paper, but in general I've seen much more lag in battles in general the more I do without resetting in between. Even the final boss (which i'd honestly expect to lag a lot given how it's a very flashy model with lots of paper effects on top of that) lagged almost unbearably the first time I played it (after having done every prior battle he sends at you beforehand), but once I restarted and fought him, it was much much less laggy.

Ah so the game merges down the parts at runtime and applies a Stroke, probably via a shader. That this is done for *every single instance* of a paper character in battle including enemies AND copies, it suddenly makes sense that sometimes Citra just...struggles with this game despite not taxing my computer any more than normal.
Though that this never happens on the overworld suggests that the game just uses static sprite frames like Mario and Luigi on the map, making it perform far more evenly. Makes sense, since I never see Paper Mario do any tweening on the map.

actually, as I've texture modded the game before, the outline is generated by the game based on the texture. It basically draws the outline around the character's whole body, but not each individual piece. They are indeed models, but the outline isn't a constant thing, it's directly generated based on the textures. Not really sure how to explain it otherwise. The sprites that do have white outlines in this sheet are from special instances in the game where the game uses a single pre-rendered texture as opposed to having split pieces.

Okay so the way it work in-game is that the character is a 3D model with this applied as a texture and it gets swapped as needed. The outline is kinda just part of the model it would seem, where the actual texture most of the time doesn't cover the whole surface so a white outline is exposed.

For the separate pieces (like the hands and arms that are put over the body) there needs to be no outline, so it doesn't overlap Mario. In-game, I'm guessing they just use some sort of shader element that draws the outline on a layer below.

how does the white outline work here? why's it only on some of the sprites?