Summary 📝

I played a bunch of Lone Echo and got inspired to re-create the zero-G mechanics from Lone Echo and Echo Arena. Since very few games have them.

I used the development presentation of Ready at Dawn over at GDC vault https://www.gdcvault.com/play/1024446. They had implementation details on the finger procedural animation and other stuff.

Features ✨

Procedural IK Hand Animations 🖐️
Full upper body IK estimation 🔎
Physically based Zero G Movement 🌌
3D Touch screen Unity UI 📱
Sample demo level with simple objectives 🎯

Missing Features ❌

Thumb IK 🤚

The thumb finger is more complicated than just a hinge joint, so I skipped it for the sake of time.

Lower Body Simulation 👜

The floating body IK physics animation I kinda skipped since I didn't have enough time for it. But should be pretty straightforward to implement.

Implementation Details 💻

Physics interactions differ q bit from Lone Echo ones. It simply comes down to not having low-level access to the physics engine in unity to implement the detailed solution from the GDC presentation. That's why I just use tweaked physics joins to make interactions feel nicer, with some additional tricks to make them more responsive.

The finger IK animation requires intersection calculations on the meshes as described by the GDC presentation. Again we don't have low level access to the physics engine and the connectivity of physics meshes to help with intersection calculations so I manually calculate them with code ripped from the unity physics package. This probably has some impact on performance but I managed to burstify the code so shouldn't be that much of an issue. I also cache each mesh.

Packages Used 📦

Demo 🎉

You can try the Windows build over at Itch.io https://simeonradivoev.itch.io/unity-echo

Screenshots 📷

Contributing 🤝

I didn't have time to implement all the features. Check out the issues to see what features are missing and need to be implemented or improved. Adding more sounds is always a bonus.

Eraile/echo-unity