Mod The Sims - Sims 2 Animations exported with baked inverse kinematics

Quote: Originally posted by ammar2

Hey all, if you've ever tried to export animations from sims 2, you'll know that they do this weird thing where they don't quite look right. This is because the animations use inverse-kinematics, the animators say where the hands/feet/head/etc should go and then the 3d animation program figures out how to move the limbs to make it happen.

In most games these inverse kinematics get "baked" into the animation files so the movement of each individual bone and limb is recorded. But unlike most games, Sims 2 uses these inverse kinematics in the final animations shipped with the game and the game engine runs the inverse kinematics as you play.

With that background out of the way, I was looking at reverse-engineering the animation format for OpenTS2 and figured out how these inverse-kinematics are set up. I haven't documented my findings but you can find some more information on the cAnimResourceConst scenegraph blocks here. With the inverse-kinematics part of the animations decoded, we are now able to play some animations from the game successfully! (Note that some animations where the hands should be pinned to objects etc still don't work well)

Since this is all done in Unity, we can actually export these animations to a format that can be imported into blender. There isn't currently a way to directly export from blender back to a sims 2 animation file without milkshape (I might make a plugin for that if I'm feeling bored). But you try to customize these animations or try to port them to future games. I have exported 10 base game animations to a .glb file available here: https://blog.ammaraskar.com/assets/...es/bakedSim.glb

If you're just curious, there is also an online model viewer available here where you can view them straight from your web browser.

What's cool is this web editor can also display other game assets, such as the reclining chair here.

Unfortunately the process to export animations fully-baked yourself will be a bit involved and need some know-how on Unity but hopefully some of you can get through it and help others out.

1. Grab and setup the OpenTS2 bake_ik_animations branch code from here https://github.com/LazyDuchess/Open...ile#development
2. Open the SimAnimationTest scene and type in the name of the animation you want

3. Right click the bakedSim and select UnityGTLF and then Export Selected as GLB

Thank you to @AlexCroft for bringing this up on the OpenTS2 repo here! https://github.com/LazyDuchess/OpenTS2/issues/59

How you import sims 2 animation into unity, I need this for my mod