just to ask
what art app can i use to mod this or?
I have my own animation program for the animation files (.anm2):
https://github.com/ShweetsStuff/anm2ed
Besides that it's a lot of editing .xml files which can be done in anything. There's a modding guide here (though it will be a bit outdated come next update)
https://wiki.weightgaming.com/en/community/games/shweets-sim